openAI-math-dataset / lean /OAI /Computability /DirectedFeedback /Games /KMSAnalyticHybridEnergyImageSplit.lean
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import Mathlib
import OAI.Computability.DirectedFeedback.Games.Derivatives
namespace OAI
noncomputable section
namespace DFVSGames.Inverse.KMSAnalyticHybridEnergy
open scoped BigOperators Classical
variable {R B U : Type*} [Ring R]
[AddCommGroup B] [Module R B] [AddCommGroup U] [Module R U]
theorem range_subtype_comp_of_surjective (W : Submodule R U)
(z : B →ₗ[R] W) (hz : Function.Surjective z) :
(W.subtype.comp z).range = W := by
ext u
constructor
· rintro ⟨b, rfl⟩
exact (z b).property
· intro hu
obtain ⟨b, hb⟩ := hz ⟨u, hu⟩
exact ⟨b, congrArg Subtype.val hb⟩
def fixedImageEquivSurjection (W : Submodule R U) :
{z : B →ₗ[R] U // z.range = W} ≃
{z : B →ₗ[R] W // Function.Surjective z} where
toFun z := ⟨z.val.codRestrict W (fun b => z.property.le (LinearMap.mem_range_self z.val b)), by
intro w
have hw : w.val ∈ z.val.range := z.property.symm ▸ w.property
obtain ⟨b, hb⟩ := hw
exact ⟨b, Subtype.ext hb⟩⟩
invFun z := ⟨W.subtype.comp z.val, range_subtype_comp_of_surjective W z.val z.property⟩
left_inv z := by
apply Subtype.ext
apply LinearMap.ext
intro b
rfl
right_inv z := by
apply Subtype.ext
apply LinearMap.ext
intro b
apply Subtype.ext
rfl
@[simp] theorem fixedImageEquivSurjection_symm_val (W : Submodule R U)
(z : {z : B →ₗ[R] W // Function.Surjective z}) :
((fixedImageEquivSurjection W).symm z).val = W.subtype.comp z.val := rfl
@[simp] theorem fixedImageEquivSurjection_apply_coe (W : Submodule R U)
(z : {z : B →ₗ[R] U // z.range = W}) (b : B) :
((fixedImageEquivSurjection W z).val b : U) = z.val b := rfl
abbrev ImageRankFrequency (q : ℕ) :=
{z : B →ₗ[R] U // Module.finrank R z.range = q}
abbrev RankImage (R U : Type*) [Ring R] [AddCommGroup U] [Module R U] (q : ℕ) :=
{W : Submodule R U // Module.finrank R W = q}
def frequencyImage (q : ℕ) (z : ImageRankFrequency (R := R) (B := B) (U := U) q) :
RankImage R U q := ⟨z.val.range, z.property⟩
def frequencyImageFiberEquiv (q : ℕ) (W : RankImage R U q) :
{z : ImageRankFrequency (R := R) (B := B) (U := U) q // frequencyImage q z = W} ≃
{z : B →ₗ[R] U // z.range = W.val} where
toFun z := ⟨z.val.val, congrArg Subtype.val z.property⟩
invFun z := ⟨⟨z.val, by rw [z.property]; exact W.property⟩, Subtype.ext z.property⟩
left_inv z := by apply Subtype.ext; apply Subtype.ext; rfl
right_inv z := by apply Subtype.ext; rfl
def rankFrequencyImageEquiv (q : ℕ) :
ImageRankFrequency (R := R) (B := B) (U := U) q ≃
Σ W : RankImage R U q, {z : B →ₗ[R] W.val // Function.Surjective z} :=
(Equiv.sigmaFiberEquiv (frequencyImage (R := R) (B := B) (U := U) q)).symm.trans
(Equiv.sigmaCongrRight fun W =>
(frequencyImageFiberEquiv q W).trans (fixedImageEquivSurjection W.val))
@[simp] theorem rankFrequencyImageEquiv_symm_val (q : ℕ)
(p : Σ W : RankImage R U q, {z : B →ₗ[R] W.val // Function.Surjective z}) :
((rankFrequencyImageEquiv q).symm p).val = p.1.val.subtype.comp p.2.val := rfl
section Sums
variable [Fintype (B →ₗ[R] U)] [Fintype (Submodule R U)]
[∀ W : Submodule R U, Fintype (B →ₗ[R] W)]
omit [Fintype (Submodule R U)] in
theorem sum_fixedImage_eq_sum_surjection (W : Submodule R U)
(weight : (B →ₗ[R] U) → ℝ) :
(∑ z : {z : B →ₗ[R] U // z.range = W}, weight z.val) =
∑ z : {z : B →ₗ[R] W // Function.Surjective z}, weight (W.subtype.comp z.val) := by
symm
apply Fintype.sum_equiv (fixedImageEquivSurjection W).symm
intro z
rfl
theorem sum_rankFrequency_eq_sum_image (q : ℕ) (weight : (B →ₗ[R] U) → ℝ) :
(∑ z : ImageRankFrequency (R := R) (B := B) (U := U) q, weight z.val) =
∑ W : RankImage R U q,
∑ z : {z : B →ₗ[R] W.val // Function.Surjective z},
weight (W.val.subtype.comp z.val) := by
calc
_ = ∑ p : Σ W : RankImage R U q,
{z : B →ₗ[R] W.val // Function.Surjective z},
weight (p.1.val.subtype.comp p.2.val) := by
symm
apply Fintype.sum_equiv (rankFrequencyImageEquiv q).symm
intro p
rfl
_ = _ := Fintype.sum_sigma _
theorem sum_filter_rank_eq_sum_image (q : ℕ) (weight : (B →ₗ[R] U) → ℝ) :
(∑ z : B →ₗ[R] U with Module.finrank R z.range = q, weight z) =
∑ W : RankImage R U q,
∑ z : {z : B →ₗ[R] W.val // Function.Surjective z},
weight (W.val.subtype.comp z.val) := by
rw [Finset.sum_subtype (p := fun z : B →ₗ[R] U => Module.finrank R z.range = q)
(Finset.univ.filter fun z : B →ₗ[R] U =>
Module.finrank R z.range = q) (by simp) weight]
exact sum_rankFrequency_eq_sum_image q weight
theorem sum_eq_sum_image_of_rank_support (q : ℕ) (weight : (B →ₗ[R] U) → ℝ)
(hsupport : ∀ z, Module.finrank R z.range ≠ q → weight z = 0) :
(∑ z : B →ₗ[R] U, weight z) =
∑ W : RankImage R U q,
∑ z : {z : B →ₗ[R] W.val // Function.Surjective z},
weight (W.val.subtype.comp z.val) := by
rw [← sum_filter_rank_eq_sum_image, Finset.sum_filter]
apply Finset.sum_congr rfl
intro z _
by_cases hz : Module.finrank R z.range = q
· simp [hz]
· simp [hz, hsupport z hz]
end Sums
variable {K V : Type*} [Field K] [AddCommGroup V] [Module K V]
def imageCoordinates (W D : Submodule K V) (h : IsCompl W D) : V ≃ₗ[K] (W × D) :=
(Submodule.prodEquivOfIsCompl W D h).symm
@[simp] theorem imageCoordinates_subtype (W D : Submodule K V) (h : IsCompl W D)
(w : W) : imageCoordinates W D h (w : V) = (w, 0) :=
Submodule.prodEquivOfIsCompl_symm_apply_left W D h w
theorem imageCoordinates_frequency {X : Type*} [AddCommGroup X] [Module K X]
(W D : Submodule K V) (h : IsCompl W D) (z : X →ₗ[K] W) :
(imageCoordinates W D h).toLinearMap.comp (W.subtype.comp z) =
z.prod (0 : X →ₗ[K] D) := by
apply LinearMap.ext
intro x
exact imageCoordinates_subtype W D h (z x)
theorem imageCoordinates_finrank [FiniteDimensional K V]
(W D : Submodule K V) (h : IsCompl W D) :
Module.finrank K W + Module.finrank K D = Module.finrank K V := by
simpa only [Module.finrank_prod] using (Submodule.prodEquivOfIsCompl W D h).finrank_eq
theorem exists_imageCoordinates (W : Submodule K V) :
∃ D : Submodule K V, ∃ e : V ≃ₗ[K] (W × D), ∀ w : W, e (w : V) = (w, 0) := by
obtain ⟨D, h⟩ := W.exists_isCompl
exact ⟨D, imageCoordinates W D h, imageCoordinates_subtype W D h⟩
end DFVSGames.Inverse.KMSAnalyticHybridEnergy
end
namespace DFVSGames.Inverse.KMSAnalyticHybridCoordinates
variable {R A W D B C : Type*} [Ring R]
[AddCommGroup A] [Module R A] [AddCommGroup W] [Module R W]
[AddCommGroup D] [Module R D] [AddCommGroup B] [Module R B]
[AddCommGroup C] [Module R C]
def compressBlock (S : (B × C) →ₗ[R] (A × (W × D))) : B →ₗ[R] (W × D) :=
(LinearMap.snd R A (W × D)).comp (S.comp (LinearMap.inl R B C))
@[simp] theorem compressBlock_apply
(S : (B × C) →ₗ[R] (A × (W × D))) (b : B) :
compressBlock S b = (S (b, 0)).2 := rfl
structure Coordinates (z : B →ₗ[R] W) where
alpha : (B × C) →ₗ[R] A
psi : (B × C) →ₗ[R] W
psi_left : psi.comp (LinearMap.inl R B C) = z
v : C →ₗ[R] D
@[ext] theorem Coordinates.ext {z : B →ₗ[R] W} {p q : Coordinates (A := A) (D := D)
(C := C) z} (ha : p.alpha = q.alpha) (hp : p.psi = q.psi) (hv : p.v = q.v) : p = q := by
cases p
cases q
cases ha
cases hp
cases hv
rfl
def assemble {z : B →ₗ[R] W} (p : Coordinates (A := A) (D := D) (C := C) z) :
(B × C) →ₗ[R] (A × (W × D)) :=
p.alpha.prod (p.psi.prod (p.v.comp (LinearMap.snd R B C)))
@[simp] theorem assemble_apply {z : B →ₗ[R] W}
(p : Coordinates (A := A) (D := D) (C := C) z) (x : B × C) :
assemble p x = (p.alpha x, p.psi x, p.v x.2) := rfl
@[simp] theorem compressBlock_assemble {z : B →ₗ[R] W}
(p : Coordinates (A := A) (D := D) (C := C) z) :
compressBlock (assemble p) = z.prod (0 : B →ₗ[R] D) := by
apply LinearMap.ext
intro b
have hp : p.psi (b, 0) = z b :=
congrArg (fun L : (B →ₗ[R] W) => L b) p.psi_left
simp [compressBlock, assemble, hp]
def extract (z : B →ₗ[R] W)
(S : {S : (B × C) →ₗ[R] (A × (W × D)) //
compressBlock S = z.prod (0 : B →ₗ[R] D)}) :
Coordinates (A := A) (D := D) (C := C) z where
alpha := (LinearMap.fst R A (W × D)).comp S.val
psi := (LinearMap.fst R W D).comp ((LinearMap.snd R A (W × D)).comp S.val)
psi_left := by
apply LinearMap.ext
intro b
exact congrArg (fun L : B →ₗ[R] (W × D) => (L b).1) S.property
v := (LinearMap.snd R W D).comp
((LinearMap.snd R A (W × D)).comp (S.val.comp (LinearMap.inr R B C)))
@[simp] theorem assemble_extract (z : B →ₗ[R] W)
(S : {S : (B × C) →ₗ[R] (A × (W × D)) //
compressBlock S = z.prod (0 : B →ₗ[R] D)}) :
assemble (extract z S) = S.val := by
apply LinearMap.ext
rintro ⟨b, c⟩
have hzero : (S.val (b, 0)).2.2 = 0 :=
congrArg (fun L : B →ₗ[R] (W × D) => (L b).2) S.property
have hlast : (S.val (b, c)).2.2 = (S.val (0, c)).2.2 := by
calc
_ = (S.val ((b, 0) + (0, c))).2.2 := by simp
_ = (S.val (b, 0)).2.2 + (S.val (0, c)).2.2 := by rw [map_add]; rfl
_ = _ := by rw [hzero, zero_add]
apply Prod.ext
· rfl
· apply Prod.ext
· rfl
· exact hlast.symm
@[simp] theorem extract_assemble {z : B →ₗ[R] W}
(p : Coordinates (A := A) (D := D) (C := C) z) :
extract z ⟨assemble p, compressBlock_assemble p⟩ = p := by
apply Coordinates.ext
· apply LinearMap.ext
intro x
rfl
· apply LinearMap.ext
intro x
rfl
· apply LinearMap.ext
intro c
rfl
def compressedFiberEquiv (z : B →ₗ[R] W) :
{S : (B × C) →ₗ[R] (A × (W × D)) //
compressBlock S = z.prod (0 : B →ₗ[R] D)} ≃
Coordinates (A := A) (D := D) (C := C) z where
toFun := extract z
invFun p := ⟨assemble p, compressBlock_assemble p⟩
left_inv S := Subtype.ext (assemble_extract z S)
right_inv := extract_assemble
theorem assemble_injective (z : B →ₗ[R] W) :
Function.Injective (assemble (R := R) (A := A) (D := D) (C := C) (z := z)) := by
intro p q h
have hh : (compressedFiberEquiv (A := A) (D := D) (C := C) z).symm p =
(compressedFiberEquiv (A := A) (D := D) (C := C) z).symm q := Subtype.ext h
exact (compressedFiberEquiv (A := A) (D := D) (C := C) z).symm.injective hh
end DFVSGames.Inverse.KMSAnalyticHybridCoordinates
namespace DFVSGames.Inverse.KMSAnalyticHybridCoordinates
variable {R A W D B C : Type*} [Field R]
[AddCommGroup A] [Module R A] [AddCommGroup W] [Module R W]
[AddCommGroup D] [Module R D] [AddCommGroup B] [Module R B]
[AddCommGroup C] [Module R C]
open DFVSGames.Appendix
private theorem psi_split_inline_KMSAnalyticHybridCoordinatesConditions {z : B →ₗ[R] W}
(p : Coordinates (A := A) (D := D) (C := C) z) (b : B) (c : C) :
p.psi (b, c) = z b + p.psi (0, c) := by
have hleft : p.psi (b, 0) = z b :=
congrArg (fun L : B →ₗ[R] W => L b) p.psi_left
calc
p.psi (b, c) = p.psi ((b, 0) + (0, c)) := by simp
_ = p.psi (b, 0) + p.psi (0, c) := p.psi.map_add _ _
_ = z b + p.psi (0, c) := by rw [hleft]
theorem hybrid_assemble_iff {z : B →ₗ[R] W}
(p : Coordinates (A := A) (D := D) (C := C) z)
(hz : Function.Surjective z) :
LinearIdentities.Hybrid (assemble p)
(LinearMap.range (LinearMap.inl R A (W × D)))
(LinearMap.range (LinearMap.inl R B C)) ↔
Function.Injective p.v ∧
Function.Surjective (p.alpha.prod (p.psi.prod (LinearMap.snd R B C))) := by
constructor
· intro h
have hzero : ∀ c : C, p.v c = 0 → c = 0 := by
intro c hc
obtain ⟨b, hb⟩ := hz (-p.psi (0, c))
have hpsi : p.psi (b, c) = 0 := by
rw [psi_split_inline_KMSAnalyticHybridCoordinatesConditions, hb, neg_add_cancel]
have hmem : (b, c) ∈ LinearMap.range (LinearMap.inl R B C) := by
apply h.2
change assemble p (b, c) ∈ LinearMap.range (LinearMap.inl R A (W × D))
refine ⟨p.alpha (b, c), ?_⟩
change (p.alpha (b, c), (0, 0)) = (p.alpha (b, c), p.psi (b, c), p.v c)
rw [hpsi, hc]
obtain ⟨b', hb'⟩ := hmem
exact (congrArg (fun x : B × C => x.2) hb').symm
refine ⟨?_, ?_⟩
· intro c d hcd
apply sub_eq_zero.mp
apply hzero
rw [map_sub, hcd, sub_self]
· rintro ⟨a, w, c⟩
obtain ⟨b, hb⟩ := hz (w - p.psi (0, c))
have hpsi : p.psi (b, c) = w := by
rw [psi_split_inline_KMSAnalyticHybridCoordinatesConditions, hb, sub_add_cancel]
have hmem : (a - p.alpha (b, c), (0, 0)) ∈ LinearMap.range (assemble p) := by
apply h.1
exact ⟨a - p.alpha (b, c), rfl⟩
obtain ⟨x, hx⟩ := hmem
have hxa : p.alpha x = a - p.alpha (b, c) :=
congrArg (fun y : A × (W × D) => y.1) hx
have hxw : p.psi x = 0 :=
congrArg (fun y : A × (W × D) => y.2.1) hx
have hxd : p.v x.2 = 0 :=
congrArg (fun y : A × (W × D) => y.2.2) hx
have hxc : x.2 = 0 := hzero _ hxd
refine ⟨x + (b, c), ?_⟩
change (p.alpha (x + (b, c)), p.psi (x + (b, c)), (x + (b, c)).2) =
(a, w, c)
apply Prod.ext
· rw [map_add, hxa, sub_add_cancel]
· apply Prod.ext
· change p.psi (x + (b, c)) = w
rw [map_add, hxw, zero_add, hpsi]
· change x.2 + c = c
rw [hxc, zero_add]
· rintro ⟨hv, htheta⟩
constructor
· rintro y ⟨a, rfl⟩
obtain ⟨x, hx⟩ := htheta (a, 0, 0)
change (p.alpha x, p.psi x, x.2) = (a, 0, 0) at hx
have hxa : p.alpha x = a := congrArg (fun y : A × (W × C) => y.1) hx
have hxw : p.psi x = 0 := congrArg (fun y : A × (W × C) => y.2.1) hx
have hxc : x.2 = 0 := congrArg (fun y : A × (W × C) => y.2.2) hx
refine ⟨x, ?_⟩
change (p.alpha x, p.psi x, p.v x.2) = (a, 0, 0)
rw [hxa, hxw, hxc, map_zero]
· intro x hx
change assemble p x ∈ LinearMap.range (LinearMap.inl R A (W × D)) at hx
obtain ⟨a, ha⟩ := hx
have hxd : p.v x.2 = 0 :=
(congrArg (fun y : A × (W × D) => y.2.2) ha).symm
have hxc : x.2 = 0 := hv (by simpa only [map_zero] using hxd)
exact ⟨x.1, Prod.ext rfl hxc.symm⟩
end DFVSGames.Inverse.KMSAnalyticHybridCoordinates
namespace DFVSGames.Inverse.KMSAnalyticHybridCoordinates
variable {R A W D B C : Type*} [Ring R]
[AddCommGroup A] [Module R A] [AddCommGroup W] [Module R W]
[AddCommGroup D] [Module R D] [AddCommGroup B] [Module R B]
[AddCommGroup C] [Module R C]
def fullCoordinates {z : B →ₗ[R] W}
(p : Coordinates (A := A) (D := D) (C := C) z) :
(B × C) →ₗ[R] (A × (W × C)) :=
p.alpha.prod (p.psi.prod (LinearMap.snd R B C))
def embedLast (v : C →ₗ[R] D) : (A × (W × C)) →ₗ[R] (A × (W × D)) :=
(LinearMap.id : A →ₗ[R] A).prodMap ((LinearMap.id : W →ₗ[R] W).prodMap v)
@[simp] theorem embedLast_apply (v : C →ₗ[R] D) (x : A × (W × C)) :
embedLast v x = (x.1, x.2.1, v x.2.2) := rfl
theorem embedLast_injective (v : C →ₗ[R] D) (hv : Function.Injective v) :
Function.Injective (embedLast (A := A) (W := W) v) := by
intro x y h
apply Prod.ext
· exact congrArg (fun u : A × (W × D) => u.1) h
· apply Prod.ext
· exact congrArg (fun u : A × (W × D) => u.2.1) h
· apply hv
exact congrArg (fun u : A × (W × D) => u.2.2) h
theorem assemble_eq_embedLast_comp {z : B →ₗ[R] W}
(p : Coordinates (A := A) (D := D) (C := C) z) :
assemble p = (embedLast p.v).comp (fullCoordinates p) := by
apply LinearMap.ext
intro x
rfl
theorem range_assemble_of_fullCoordinates_surjective {z : B →ₗ[R] W}
(p : Coordinates (A := A) (D := D) (C := C) z)
(hp : Function.Surjective (fullCoordinates p)) :
(assemble p).range = (embedLast (A := A) (W := W) p.v).range := by
rw [assemble_eq_embedLast_comp, LinearMap.range_comp,
LinearMap.range_eq_top.mpr hp, Submodule.map_top]
theorem finrank_assemble {z : B →ₗ[R] W}
(p : Coordinates (A := A) (D := D) (C := C) z)
(hv : Function.Injective p.v) (hp : Function.Surjective (fullCoordinates p)) :
Module.finrank R (assemble p).range = Module.finrank R (A × (W × C)) := by
rw [range_assemble_of_fullCoordinates_surjective p hp]
exact LinearMap.finrank_range_of_inj (embedLast_injective p.v hv)
theorem ker_assemble {z : B →ₗ[R] W}
(p : Coordinates (A := A) (D := D) (C := C) z)
(hv : Function.Injective p.v) :
(assemble p).ker = (fullCoordinates p).ker := by
rw [assemble_eq_embedLast_comp]
exact LinearMap.ker_comp_of_ker_eq_bot _
(LinearMap.ker_eq_bot.mpr (embedLast_injective p.v hv))
end DFVSGames.Inverse.KMSAnalyticHybridCoordinates
namespace DFVSGames.Inverse.KMSAnalyticHybridCoordinates
variable {R A W D B C : Type*} [Field R]
[AddCommGroup A] [Module R A] [AddCommGroup W] [Module R W]
[AddCommGroup D] [Module R D] [AddCommGroup B] [Module R B]
[AddCommGroup C] [Module R C]
open DFVSGames.Appendix
def hybridFiberEquiv (z : B →ₗ[R] W) (hz : Function.Surjective z) :
{S : (B × C) →ₗ[R] (A × (W × D)) //
compressBlock S = z.prod (0 : B →ₗ[R] D) ∧
LinearIdentities.Hybrid S
(LinearMap.range (LinearMap.inl R A (W × D)))
(LinearMap.range (LinearMap.inl R B C))} ≃
{p : Coordinates (A := A) (D := D) (C := C) z //
Function.Injective p.v ∧ Function.Surjective (fullCoordinates p)} where
toFun S := ⟨extract z ⟨S.val, S.property.1⟩, by
apply (hybrid_assemble_iff _ hz).mp
rw [assemble_extract]
exact S.property.2⟩
invFun p := ⟨assemble p.val, compressBlock_assemble p.val,
(hybrid_assemble_iff p.val hz).mpr p.property⟩
left_inv S := by
apply Subtype.ext
exact assemble_extract z ⟨S.val, S.property.1⟩
right_inv p := by
apply Subtype.ext
exact extract_assemble p.val
theorem hybridFiber_finrank (z : B →ₗ[R] W) (hz : Function.Surjective z)
(S : (B × C) →ₗ[R] (A × (W × D)))
(hc : compressBlock S = z.prod (0 : B →ₗ[R] D))
(hh : LinearIdentities.Hybrid S
(LinearMap.range (LinearMap.inl R A (W × D)))
(LinearMap.range (LinearMap.inl R B C))) :
Module.finrank R S.range = Module.finrank R (A × (W × C)) := by
let p := (hybridFiberEquiv (A := A) (D := D) (C := C) z hz) ⟨S, hc, hh⟩
have he : assemble p.val = S := assemble_extract z ⟨S, hc⟩
rw [← he]
exact finrank_assemble p.val p.property.1 p.property.2
end DFVSGames.Inverse.KMSAnalyticHybridCoordinates
namespace DFVSGames.Inverse.KMSAnalytic
noncomputable section
open scoped BigOperators Classical
open DFVSGames.Integration.BinaryLinear (F2)
open DFVSGames.Fourier.MatrixFourier
variable {E F I : Type*}
[AddCommGroup E] [Module F2 E] [AddCommGroup F] [Module F2 F]
[AddCommGroup I] [Module F2 I]
[FiniteDimensional F2 E] [FiniteDimensional F2 F] [FiniteDimensional F2 I]
[Fintype (E →ₗ[F2] F)] [Fintype (F →ₗ[F2] E)]
[Fintype (I →ₗ[F2] F)] [Fintype (F →ₗ[F2] I)]
def smallCoeff (ι : I →ₗ[F2] E) (f : (E →ₗ[F2] F) → ℝ)
(T : F →ₗ[F2] I) : ℝ :=
if Function.Surjective T then linearCoeff f (ι.comp T) else 0
def smallComponent (ι : I →ₗ[F2] E) (f : (E →ₗ[F2] F) → ℝ) :
(I →ₗ[F2] F) → ℝ := synthesis (smallCoeff ι f)
omit [FiniteDimensional F2 E] [Fintype (F →ₗ[F2] E)] in
@[simp] theorem coeff_smallComponent (ι : I →ₗ[F2] E)
(f : (E →ₗ[F2] F) → ℝ) (T : F →ₗ[F2] I) :
linearCoeff (smallComponent ι f) T = smallCoeff ι f T :=
coeff_synthesis _ _
omit [FiniteDimensional F2 E] [Fintype (F →ₗ[F2] E)] in
theorem coeff_smallComponent_of_surjective (ι : I →ₗ[F2] E)
(f : (E →ₗ[F2] F) → ℝ) (T : F →ₗ[F2] I)
(hT : Function.Surjective T) :
linearCoeff (smallComponent ι f) T = linearCoeff f (ι.comp T) := by
simp only [coeff_smallComponent, smallCoeff, ite_eq_left hT]
omit [FiniteDimensional F2 E] [Fintype (F →ₗ[F2] E)] in
theorem coeff_smallComponent_of_not_surjective (ι : I →ₗ[F2] E)
(f : (E →ₗ[F2] F) → ℝ) (T : F →ₗ[F2] I)
(hT : ¬ Function.Surjective T) : linearCoeff (smallComponent ι f) T = 0 := by
simp only [coeff_smallComponent, smallCoeff, ite_eq_right hT]
omit [FiniteDimensional F2 E] [Fintype (F →ₗ[F2] E)] in
theorem smallComponent_energy (ι : I →ₗ[F2] E) (f : (E →ₗ[F2] F) → ℝ) :
(𝔼 X, smallComponent ι f X ^ 2) =
∑ T ∈ Finset.univ.filter (fun T : F →ₗ[F2] I => Function.Surjective T),
linearCoeff f (ι.comp T) ^ 2 := by
rw [smallComponent, synthesis_energy, Finset.sum_filter]
apply Finset.sum_congr rfl
intro T _
by_cases hT : Function.Surjective T <;> simp [smallCoeff, hT]
omit [FiniteDimensional F2 E] [Fintype (F →ₗ[F2] E)] in
theorem rankComponent_smallComponent (ι : I →ₗ[F2] E)
(f : (E →ₗ[F2] F) → ℝ) :
rankComponent (Module.finrank F2 I) (smallComponent ι f) = smallComponent ι f := by
apply eq_of_coeff_eq
intro T
simp only [rankComponent, coeff_component, coeff_smallComponent]
by_cases hT : Function.Surjective T
· have hr : Module.finrank F2 T.range = Module.finrank F2 I :=
Submodule.eq_top_iff_finrank_eq.mp (LinearMap.range_eq_top.mpr hT)
simp [hr]
· simp [smallCoeff, hT]
omit [FiniteDimensional F2 E] [FiniteDimensional F2 F] [FiniteDimensional F2 I] [Fintype (E →ₗ[F2] F)] [Fintype (F →ₗ[F2] E)] [Fintype (I →ₗ[F2] F)] [Fintype (F →ₗ[F2] I)] in
theorem ker_comp_of_injective (ι : I →ₗ[F2] E) (hι : Function.Injective ι)
(T : F →ₗ[F2] I) : (ι.comp T).ker = T.ker :=
LinearMap.ker_comp_of_ker_eq_bot T (LinearMap.ker_eq_bot.mpr hι)
omit [FiniteDimensional F2 E] [FiniteDimensional F2 F] [FiniteDimensional F2 I] [Fintype (F →ₗ[F2] E)] [Fintype (I →ₗ[F2] F)] [Fintype (F →ₗ[F2] I)] in
theorem smallCoeff_eq_of_kernel_coeff_const (ι κ : I →ₗ[F2] E)
(hι : Function.Injective ι) (hκ : Function.Injective κ)
(f : (E →ₗ[F2] F) → ℝ)
(hcoeff : ∀ S T : F →ₗ[F2] E,
S.ker = T.ker → linearCoeff f S = linearCoeff f T) :
smallCoeff ι f = smallCoeff κ f := by
funext T
unfold smallCoeff
by_cases hT : Function.Surjective T
· simp only [ite_eq_left hT]
exact hcoeff _ _ ((ker_comp_of_injective ι hι T).trans
(ker_comp_of_injective κ hκ T).symm)
· simp only [ite_eq_right hT]
omit [FiniteDimensional F2 E] [FiniteDimensional F2 F] [FiniteDimensional F2 I]
[Fintype (F →ₗ[F2] E)] [Fintype (I →ₗ[F2] F)] in
theorem smallComponent_eq_of_kernel_coeff_const (ι κ : I →ₗ[F2] E)
(hι : Function.Injective ι) (hκ : Function.Injective κ)
(f : (E →ₗ[F2] F) → ℝ)
(hcoeff : ∀ S T : F →ₗ[F2] E,
S.ker = T.ker → linearCoeff f S = linearCoeff f T) :
smallComponent ι f = smallComponent κ f :=
congrArg synthesis (smallCoeff_eq_of_kernel_coeff_const ι κ hι hκ f hcoeff)
omit [FiniteDimensional F2 E] [Fintype (F →ₗ[F2] E)] in
theorem smallComponent_orthogonal (ι : I →ₗ[F2] E)
(f : (E →ₗ[F2] F) → ℝ) (g : (I →ₗ[F2] F) → ℝ)
(hg : ∀ T : F →ₗ[F2] I, Function.Surjective T → linearCoeff g T = 0) :
(𝔼 X, smallComponent ι f X * g X) = 0 := by
rw [← linear_parseval_inner]
apply Finset.sum_eq_zero
intro T _
rw [coeff_smallComponent]
by_cases hT : Function.Surjective T
· rw [hg T hT, mul_zero]
· simp [smallCoeff, hT]
theorem smallComponent_energy_le (ι : I →ₗ[F2] E) (hι : Function.Injective ι)
(f : (E →ₗ[F2] F) → ℝ) :
(𝔼 X, smallComponent ι f X ^ 2) ≤ 𝔼 X, f X ^ 2 := by
have hinj : Function.Injective (fun T : F →ₗ[F2] I => ι.comp T) := by
intro T U hTU
apply LinearMap.ext
intro x
apply hι
exact congrArg (fun S : F →ₗ[F2] E => S x) hTU
rw [smallComponent_energy, ← linear_parseval]
calc
_ = ∑ S ∈ (Finset.univ.filter (fun T : F →ₗ[F2] I => Function.Surjective T)).image
(fun T => ι.comp T), linearCoeff f S ^ 2 := by
rw [Finset.sum_image]
intro T _ U _ hTU
exact hinj hTU
_ ≤ ∑ S, linearCoeff f S ^ 2 :=
Finset.sum_le_sum_of_subset_of_nonneg (Finset.subset_univ _)
(fun S _ _ => sq_nonneg _)
end
end DFVSGames.Inverse.KMSAnalytic
namespace DFVSGames.Inverse.KMSKernelOrbits
noncomputable section
variable {K E F : Type*} [DivisionRing K]
[AddCommGroup E] [Module K E] [AddCommGroup F] [Module K F]
def rangeEquivOfKerEq (S T : F →ₗ[K] E) (hker : S.ker = T.ker) :
S.range ≃ₗ[K] T.range :=
S.quotKerEquivRange.symm ≪≫ₗ
Submodule.quotEquivOfEq S.ker T.ker hker ≪≫ₗ T.quotKerEquivRange
theorem rangeEquivOfKerEq_apply (S T : F →ₗ[K] E) (hker : S.ker = T.ker) (x : F) :
(rangeEquivOfKerEq S T hker ⟨S x, ⟨x, rfl⟩⟩ : E) = T x := by
change (T.quotKerEquivRange ((Submodule.quotEquivOfEq S.ker T.ker hker)
(S.quotKerEquivRange.symm ⟨S x, ⟨x, rfl⟩⟩)) : E) = T x
have hs : (⟨S x, ⟨x, rfl⟩⟩ : S.range) =
S.quotKerEquivRange (Submodule.Quotient.mk x) := rfl
rw [hs, LinearEquiv.symm_apply_apply]
rfl
theorem exists_postcomp_equiv_of_ker_eq (S T : F →ₗ[K] E)
[FiniteDimensional K S.range] (hker : S.ker = T.ker) :
∃ g : E ≃ₗ[K] E, g.toLinearMap.comp S = T := by
obtain ⟨g, hg⟩ := Submodule.exists_linearEquiv_restrict_eq
(rangeEquivOfKerEq S T hker)
refine ⟨g, ?_⟩
ext x
change g (S x) = T x
exact (hg ⟨S x, ⟨x, rfl⟩⟩).symm.trans (rangeEquivOfKerEq_apply S T hker x)
theorem ker_eq_iff_exists_postcomp_equiv (S T : F →ₗ[K] E)
[FiniteDimensional K S.range] :
S.ker = T.ker ↔ ∃ g : E ≃ₗ[K] E, g.toLinearMap.comp S = T := by
constructor
· exact exists_postcomp_equiv_of_ker_eq S T
· rintro ⟨g, rfl⟩
ext x
simp
end
end DFVSGames.Inverse.KMSKernelOrbits
namespace DFVSGames.Inverse.KMSBasisInvariant
noncomputable section
open scoped BigOperators
open DFVSGames.Fourier.MatrixCharacters
open DFVSGames.Fourier.MatrixFourier
variable {E F : Type*} [AddCommGroup E] [Module F2 E]
[AddCommGroup F] [Module F2 F]
def primalChange (g : E ≃ₗ[F2] E) : (E →ₗ[F2] F) ≃ (E →ₗ[F2] F) where
toFun X := X.comp g.toLinearMap
invFun X := X.comp g.symm.toLinearMap
left_inv X := by ext x; simp
right_inv X := by ext x; simp
def frequencyChange (g : E ≃ₗ[F2] E) : (F →ₗ[F2] E) ≃ (F →ₗ[F2] E) where
toFun S := g.toLinearMap.comp S
invFun S := g.symm.toLinearMap.comp S
left_inv S := by ext x; simp
right_inv S := by ext x; simp
def IsBasisInvariant (f : (E →ₗ[F2] F) → ℝ) : Prop :=
∀ (g : E ≃ₗ[F2] E) X, f (X.comp g.toLinearMap) = f X
theorem character_change (g : E ≃ₗ[F2] E) (S : F →ₗ[F2] E)
(X : E →ₗ[F2] F) :
linearTraceCharacter (g.toLinearMap.comp S) X =
linearTraceCharacter S (X.comp g.toLinearMap) := by
simp only [linearTraceCharacter_apply, linearTracePair, LinearMap.comp_assoc]
variable [Fintype (E →ₗ[F2] F)]
theorem coefficient_change (f : (E →ₗ[F2] F) → ℝ)
(hf : IsBasisInvariant f) (g : E ≃ₗ[F2] E) (S : F →ₗ[F2] E) :
linearCoeff f (g.toLinearMap.comp S) = linearCoeff f S := by
unfold linearCoeff
apply Fintype.expect_equiv (primalChange g)
intro X
change f X * (linearTraceCharacter (g.toLinearMap.comp S) X).re =
f (X.comp g.toLinearMap) * (linearTraceCharacter S (X.comp g.toLinearMap)).re
rw [character_change, hf g X]
def frequencyRank (S : F →ₗ[F2] E) : ℕ := Module.finrank F2 (LinearMap.range S)
omit [Fintype (E →ₗ[F2] F)] in
theorem frequencyRank_change (g : E ≃ₗ[F2] E) (S : F →ₗ[F2] E) :
frequencyRank (g.toLinearMap.comp S) = frequencyRank S := by
unfold frequencyRank
rw [LinearMap.range_comp, g.finrank_map_eq]
variable [Fintype (F →ₗ[F2] E)]
def rankProjection (i : ℕ) (f : (E →ₗ[F2] F) → ℝ) (X : E →ₗ[F2] F) : ℝ :=
∑ S, if frequencyRank S = i then linearCoeff f S * (linearTraceCharacter S X).re else 0
theorem rankProjection_invariant (i : ℕ) (f : (E →ₗ[F2] F) → ℝ)
(hf : IsBasisInvariant f) : IsBasisInvariant (rankProjection i f) := by
intro g X
unfold rankProjection
apply Fintype.sum_equiv (frequencyChange g)
intro S
change (if frequencyRank S = i then
linearCoeff f S * (linearTraceCharacter S (X.comp g.toLinearMap)).re else 0) =
if frequencyRank (g.toLinearMap.comp S) = i then
linearCoeff f (g.toLinearMap.comp S) *
(linearTraceCharacter (g.toLinearMap.comp S) X).re else 0
rw [frequencyRank_change, coefficient_change f hf, character_change]
end
end DFVSGames.Inverse.KMSBasisInvariant
end OAI