File size: 10,566 Bytes
f0f05de
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
import OAI.Combinatorics.BalancedRyser.Local.AlignedFreeCoordinates
import OAI.Combinatorics.BalancedRyser.Local.AlignmentNoBias
import OAI.Combinatorics.BalancedRyser.Probability.FiniteConditionalRatios

namespace OAI

namespace Balanced.AlignedListProbability

open Local PartialAlignment

noncomputable section
attribute [local instance] Classical.propDecidable

variable {F : Type*} [Field F] [Fintype F] [DecidableEq F]

theorem conditioned_alignment_suffix_observed {ι : Type*} [DecidableEq ι]
    (T : ι → FourTuple F) (L : ι → Line F) (post pre : List ι)
    (hT : ∀ i ∈ post ++ pre, Function.Injective (T i).generator)
    (hg : ∀ i ∈ post ++ pre, ∀ j, (T i).generator j ≠ (L i).1)
    (horder : SmallReuseOrder (fun i => generatorSet (T i)) (post ++ pre))
    (H E : MergedPairs F → Prop)
    (hH : ∀ M N, (∀ d ∈ pre.toFinset.biUnion (fun i => generatorSet (T i)),
      M d = N d) → (H M ↔ H N))
    (hE : ∀ M N, (∀ d ∈ pre.toFinset.biUnion (fun i => generatorSet (T i)),
      M d = N d) → (E M ↔ E N)) :
    conditionedOffsetProbability (fun M => ListAligned T L (post ++ pre) M ∧ H M) E =
      conditionedOffsetProbability (fun M => ListAligned T L pre M ∧ H M) E := by
  have hnum := list_alignment_append_weighted T L post pre hT hg horder
    (fun M => H M ∧ E M) (fun M N h => and_congr (hH M N h) (hE M N h))
  have hden := list_alignment_append_weighted T L post pre hT hg horder H hH
  have hn :
      offsetProbability (fun M => (ListAligned T L (post ++ pre) M ∧ H M) ∧ E M) =
        ((Fintype.card F : ℝ)⁻¹ ^ 4) ^ post.length *
          offsetProbability (fun M => (ListAligned T L pre M ∧ H M) ∧ E M) := by
    simpa only [and_assoc, and_left_comm, and_comm] using hnum
  have hd : offsetProbability (fun M => ListAligned T L (post ++ pre) M ∧ H M) =
      ((Fintype.card F : ℝ)⁻¹ ^ 4) ^ post.length *
        offsetProbability (fun M => ListAligned T L pre M ∧ H M) := by
    simpa only [and_comm] using hden
  unfold conditionedOffsetProbability
  rw [hn, hd]
  have hc : ((Fintype.card F : ℝ)⁻¹ ^ 4) ^ post.length ≠ 0 := by positivity
  exact mul_div_mul_left _ _ hc

theorem conditioned_alignment_step {ι : Type*} [DecidableEq ι]
    (T : ι → FourTuple F) (L : ι → Line F) (post pre : List ι) (i : ι)
    (hT : ∀ k ∈ post ++ i :: pre, Function.Injective (T k).generator)
    (hg : ∀ k ∈ post ++ i :: pre, ∀ j, (T k).generator j ≠ (L k).1)
    (horder : SmallReuseOrder (fun k => generatorSet (T k)) (post ++ i :: pre))
    (a : MergedPairs F) (ha : ListAligned T L pre a)
    (E : MergedPairs F → Prop)
    (hE : ∀ M N, (∀ d ∈ (i :: pre).toFinset.biUnion (fun k => generatorSet (T k)),
      M d = N d) → (E M ↔ E N)) :
    conditionedOffsetProbability
      (fun M => ListAligned T L (post ++ i :: pre) M ∧
        ∀ d ∈ pre.toFinset.biUnion (fun k => generatorSet (T k)), M d = a d) E =
    conditionedOffsetProbability
      (fun M => (∀ j, OnLine (tuplePoint M (T i) j) (L i)) ∧
        ∀ d ∈ pre.toFinset.biUnion (fun k => generatorSet (T k)), M d = a d) E := by
  let H : MergedPairs F → Prop :=
    fun M => ∀ d ∈ pre.toFinset.biUnion (fun k => generatorSet (T k)), M d = a d
  have hH (M N : MergedPairs F)
      (h : ∀ d ∈ (i :: pre).toFinset.biUnion (fun k => generatorSet (T k)),
        M d = N d) : H M ↔ H N := by
    have heq (d) (hd : d ∈ pre.toFinset.biUnion (fun k => generatorSet (T k))) :
        M d = N d := by
      apply h
      rcases Finset.mem_biUnion.mp hd with ⟨k, hk, hdk⟩
      exact Finset.mem_biUnion.mpr ⟨k, by simpa using Or.inr hk, hdk⟩
    constructor <;> intro hm d hd
    · exact (heq d hd).symm.trans (hm d hd)
    · exact (heq d hd).trans (hm d hd)
  have hs := conditioned_alignment_suffix_observed T L post (i :: pre)
    hT hg horder H E hH hE
  have hcollapse : (fun M => ListAligned T L (i :: pre) M ∧ H M) =
      (fun M => (∀ j, OnLine (tuplePoint M (T i) j) (L i)) ∧ H M) := by
    funext M
    apply propext
    constructor
    · rintro ⟨hal, hfix⟩
      exact ⟨hal i (by simp), hfix⟩
    · rintro ⟨hcur, hfix⟩
      refine ⟨?_, hfix⟩
      have hp : ListAligned T L pre M :=
        (listAligned_agree T L pre M a hfix).mpr ha
      intro k hk
      rcases List.mem_cons.mp hk with rfl | hk
      · exact hcur
      · exact hp k hk
  rw [hcollapse] at hs
  exact hs

theorem current_tuple_conditional_ratio
    (T : FourTuple F) (hT : Function.Injective T.generator)
    (g : Direction F) (c : F) (D : Finset (Direction F)) (a : MergedPairs F)
    (E : (Fin 4 → Bool → F) → Prop) :
    conditionedOffsetProbability
      (fun M => (∀ d ∈ D, M d = a d) ∧ ∀ j, OnLine (tuplePoint M T j) (g,c))
      (fun M => E (fun j => M (T.generator j))) =
      ((PMF.uniformOfFintype (PartialOffsets (exposedTupleIndices T D)
        (fun j => a (T.generator j)))).toOuterMeasure
        {o | (∀ j, OnLine (TupleAlignment.tuplePositionEquiv T.generator
          (TupleAlignment.adjacent_ne_of_injective T hT) T.side o.1 j) (g,c)) ∧ E o.1}).toReal /
      ((PMF.uniformOfFintype (PartialOffsets (exposedTupleIndices T D)
        (fun j => a (T.generator j)))).toOuterMeasure
        {o | ∀ j, OnLine (TupleAlignment.tuplePositionEquiv T.generator
          (TupleAlignment.adjacent_ne_of_injective T hT) T.side o.1 j) (g,c)}).toReal := by
  let P := PartialOffsets (exposedTupleIndices T D) (fun j => a (T.generator j))
  let B : Set (Fin 4 → Bool → F) :=
    {o | ∀ j, OnLine (TupleAlignment.tuplePositionEquiv T.generator
      (TupleAlignment.adjacent_ne_of_injective T hT) T.side o j) (g,c)}
  have hm := global_exposed_tuple_law T hT D a
  rw [partialOffsets_conditional_law] at hm
  have hr := marginal_conditional_ratio (PMF.uniformOfFintype (MergedPairs F))
    ((PMF.uniformOfFintype P).map Subtype.val)
    {M | ∀ d ∈ D, M d = a d} (ConditionalRestriction.fixed_supported (fun d => d ∈ D) a)
    (fun M j => M (T.generator j)) hm B {o | E o}
  rw [PMF.toOuterMeasure_map_apply, PMF.toOuterMeasure_map_apply] at hr
  have hp (K : MergedPairs F → Prop) : offsetProbability K =
      ((PMF.uniformOfFintype (MergedPairs F)).toOuterMeasure {M | K M}).toReal :=
    (FiniteUniformFibers.probability_eq_sum K).symm
  unfold conditionedOffsetProbability
  rw [hp, hp]
  simpa only [P, B, Set.preimage_ofPred_eq, ← Set.ofPred_and, and_assoc,
    tuplePoint, constituent, TupleAlignment.tuplePositionEquiv_apply] using hr

abbrev CurrentFreeCoordinates (T : FourTuple F) (D : Finset (Direction F)) :=
  {j : Fin 4 // j ∈ freePositions (exposedTupleIndices T D)} → F

def generateCurrentTupleOffsets
    (T : FourTuple F) (hT : Function.Injective T.generator)
    (g : Direction F) (hg : ∀ j, T.generator j ≠ g) (c : F)
    (D : Finset (Direction F)) (hD : (exposedTupleIndices T D).card ≤ 1)
    (a : MergedPairs F) (x : CurrentFreeCoordinates T D) : Fin 4 → Bool → F :=
  ((alignedFreeCoordinatesEquiv T.generator (TupleAlignment.adjacent_ne_of_injective T hT)
    T.side g hg c (exposedTupleIndices T D) hD (fun j => a (T.generator j))).symm x).1.1

theorem current_tuple_generated_probability
    (T : FourTuple F) (hT : Function.Injective T.generator)
    (g : Direction F) (hg : ∀ j, T.generator j ≠ g) (c : F)
    (D : Finset (Direction F)) (hD : (exposedTupleIndices T D).card ≤ 1)
    (a : MergedPairs F) (E : (Fin 4 → Bool → F) → Prop) :
    conditionedOffsetProbability
      (fun M => (∀ d ∈ D, M d = a d) ∧ ∀ j, OnLine (tuplePoint M T j) (g,c))
      (fun M => E (fun j => M (T.generator j))) =
    ((PMF.uniformOfFintype (CurrentFreeCoordinates T D)).toOuterMeasure
      {x | E (generateCurrentTupleOffsets T hT g hg c D hD a x)}).toReal := by
  rw [current_tuple_conditional_ratio T hT g c D a E]
  have hm := alignedPartial_conditional_law T.generator
    (TupleAlignment.adjacent_ne_of_injective T hT) T.side g hg c
    (exposedTupleIndices T D) hD (fun j => a (T.generator j))
  have h := congrArg (fun law => (law.toOuterMeasure {o | E o.1}).toReal) hm
  rw [filter_outer_ratio, ENNReal.toReal_div, PMF.toOuterMeasure_map_apply] at h
  exact h

omit [Field F] [Fintype F] in

theorem step_exposed_count {ι : Type*} [DecidableEq ι]
    (T : ι → FourTuple F) (post pre : List ι) (i : ι)
    (hi : Function.Injective (T i).generator)
    (horder : SmallReuseOrder (fun k => generatorSet (T k)) (post ++ i :: pre)) :
    (exposedTupleIndices (T i) (pre.toFinset.biUnion (fun k => generatorSet (T k)))).card ≤ 1 := by
  rw [card_exposedTupleIndices (T i) hi]
  exact (smallReuseOrder_suffix (fun k => generatorSet (T k)) post (i :: pre) horder).2

theorem full_aligned_step_generated_probability {ι : Type*} [DecidableEq ι]
    (T : ι → FourTuple F) (L : ι → Line F) (post pre : List ι) (i : ι)
    (hT : ∀ k ∈ post ++ i :: pre, Function.Injective (T k).generator)
    (hg : ∀ k ∈ post ++ i :: pre, ∀ j, (T k).generator j ≠ (L k).1)
    (horder : SmallReuseOrder (fun k => generatorSet (T k)) (post ++ i :: pre))
    (a : MergedPairs F) (ha : ListAligned T L pre a)
    (E : (Fin 4 → Bool → F) → Prop) :
    let D := pre.toFinset.biUnion (fun k => generatorSet (T k))
    conditionedOffsetProbability
      (fun M => ListAligned T L (post ++ i :: pre) M ∧ ∀ d ∈ D, M d = a d)
      (fun M => E (fun j => M ((T i).generator j))) =
    ((PMF.uniformOfFintype (CurrentFreeCoordinates (T i) D)).toOuterMeasure
      {x | E (generateCurrentTupleOffsets (T i) (hT i (by simp)) (L i).1
        (hg i (by simp)) (L i).2 D (step_exposed_count T post pre i (hT i (by simp)) horder)
        a x)}).toReal := by
  let D := pre.toFinset.biUnion (fun k => generatorSet (T k))
  have hE (M N : MergedPairs F)
      (h : ∀ d ∈ (i :: pre).toFinset.biUnion (fun k => generatorSet (T k)), M d = N d) :
      E (fun j => M ((T i).generator j)) ↔ E (fun j => N ((T i).generator j)) := by
    have heq : (fun j => M ((T i).generator j)) = (fun j => N ((T i).generator j)) := by
      funext j
      apply h
      exact Finset.mem_biUnion.mpr ⟨i, by simp, by simp [generatorSet]⟩
    rw [heq]
  have hs := conditioned_alignment_step T L post pre i hT hg horder a ha
    (fun M => E (fun j => M ((T i).generator j))) hE
  have hc := current_tuple_generated_probability (T i) (hT i (by simp)) (L i).1
    (hg i (by simp)) (L i).2 D (step_exposed_count T post pre i (hT i (by simp)) horder) a E
  exact hs.trans (by simpa only [and_comm, Prod.eta] using hc)

end
end Balanced.AlignedListProbability

end OAI