openAI-math-dataset / lean /OAI /Probability /ParisiFinite /InnerRootYCoordinates.lean
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import Mathlib
import OAI.Probability.ParisiFinite.OrdinaryInverseSpecial
import OAI.Probability.ParisiFinite.RestrictLeft
namespace OAI
/-! Inner Root Y Coordinates. -/
noncomputable section
open scoped BigOperators ComplexConjugate InnerProductSpace Topology ComplexOrder
open Filter
open scoped BigOperators
open scoped Matrix Matrix.Norms.L2Operator ComplexConjugate
open scoped InnerProductSpace ComplexConjugate
open Filter Topology
open Filter Set Topology
open scoped InnerProductSpace ComplexConjugate Topology
open scoped InnerProductSpace
namespace CoherentFock
open PointedTree RootSpin Complex
variable {E : Type*} [NormedAddCommGroup E] [InnerProductSpace ℂ E]
theorem inner_rootY_coordinates (x y : SpinSpace E) :
⟪SpinOperators.act Y x,y⟫_ℂ=I*⟪x 1,y 0⟫_ℂ-I*⟪x 0,y 1⟫_ℂ := by
simp [PiLp.inner_apply,SpinOperators.act_apply,Fin.sum_univ_two,Y,
inner_smul_left,sub_eq_add_neg]
theorem inner_rootY_spinW_same_plus (d e : E) (x y : PreSpin E) (hx : x 1=0) (hy : y 1=0) :
⟪SpinOperators.act Y (spinW d (spinCoe x)),spinW e (spinCoe y)⟫_ℂ=0 := by
rw [inner_rootY_coordinates]
simp [hx,hy]
theorem inner_rootY_spinW_same_minus (d e : E) (x y : PreSpin E) (hx : x 0=0) (hy : y 0=0) :
⟪SpinOperators.act Y (spinW d (spinCoe x)),spinW e (spinCoe y)⟫_ℂ=0 := by
rw [inner_rootY_coordinates]
simp [hx,hy]
def hugePacket (R : ℝ) (d e : E) (xp xm : PreSpin E) : SpinSpace E :=
spinW (R • d) (spinCoe xp)+spinW (R • e) (spinCoe xm)
theorem norm_hugePacket_le (R : ℝ) (d e : E) (xp xm : PreSpin E) :
‖hugePacket R d e xp xm‖≤ spinMass xp+spinMass xm := by
apply (norm_add_le _ _).trans
exact add_le_add ((norm_spinW _ _).trans_le (norm_spinCoe_le_mass _))
((norm_spinW _ _).trans_le (norm_spinCoe_le_mass _))
theorem inner_rootY_hugePacket (R : ℝ) (d e : E) (xp xm yp ym : PreSpin E)
(hxp : xp 1=0) (hxm : xm 0=0) (hyp : yp 1=0) (hym : ym 0=0) :
⟪SpinOperators.act Y (hugePacket R d e xp xm),hugePacket R d e yp ym⟫_ℂ=
⟪SpinOperators.act Y (spinW (R • d) (spinCoe xp)),spinW (R • e) (spinCoe ym)⟫_ℂ+
⟪SpinOperators.act Y (spinW (R • e) (spinCoe xm)),spinW (R • d) (spinCoe yp)⟫_ℂ := by
simp only [hugePacket,map_add,inner_add_left,inner_add_right,
inner_rootY_spinW_same_plus _ _ _ _ hxp hyp,inner_rootY_spinW_same_minus _ _ _ _ hxm hym,
zero_add,add_zero]
exact add_comm _ _
theorem tendsto_inner_rootY_hugePacket {α : Type*} {l : Filter α}
(R : α → ℝ) (d e : α → E) (xp xm yp ym : α → PreSpin E)
(hR : Tendsto R l atTop) (B A δ : ℝ) (hA : 0≤ A) (hδ : 0<δ)
(hxp : ∀ᶠ a in l, SpinRadiusLE (xp a) B ∧ spinMass (xp a)≤ A)
(hxm : ∀ᶠ a in l, SpinRadiusLE (xm a) B ∧ spinMass (xm a)≤ A)
(hyp : ∀ᶠ a in l, SpinRadiusLE (yp a) B ∧ spinMass (yp a)≤ A)
(hym : ∀ᶠ a in l, SpinRadiusLE (ym a) B ∧ spinMass (ym a)≤ A)
(hs : ∀ᶠ a in l, xp a 1=0 ∧ xm a 0=0 ∧ yp a 1=0 ∧ ym a 0=0)
(hsep : ∀ᶠ a in l, δ≤ ‖d a-e a‖) :
Tendsto (fun a => ⟪SpinOperators.act Y (hugePacket (R a) (d a) (e a) (xp a) (xm a)),
hugePacket (R a) (d a) (e a) (yp a) (ym a)⟫_ℂ) l (𝓝 0) := by
have hP : ∀ᶠ a : α in l, matrixMass Y≤ matrixMass Y := Filter.Eventually.of_forall (fun _ => le_rfl)
have h1 := rapid_decay_spin_matrix R d e xp ym (fun _ => Y) hR B A (matrixMass Y) δ hA
(matrixMass_nonneg _) hδ hxp hym hP hsep 0
have hsep' : ∀ᶠ a in l, δ≤ ‖e a-d a‖ := hsep.mono (fun a ha => by rwa [norm_sub_rev])
have h2 := rapid_decay_spin_matrix R e d xm yp (fun _ => Y) hR B A (matrixMass Y) δ hA
(matrixMass_nonneg _) hδ hxm hyp hP hsep' 0
simp only [pow_zero,one_mul] at h1 h2
have h1' := tendsto_zero_iff_norm_tendsto_zero.mpr h1
have h2' := tendsto_zero_iff_norm_tendsto_zero.mpr h2
have hh := h1'.add h2'
simp only [add_zero] at hh
apply hh.congr'
filter_upwards [hs] with a ha
exact (inner_rootY_hugePacket (R a) (d a) (e a) (xp a) (xm a) (yp a) (ym a)
ha.1 ha.2.1 ha.2.2.1 ha.2.2.2).symm
theorem inner_rootY_error_bound (x y u v : SpinSpace E) :
‖⟪SpinOperators.act Y x,y⟫_ℂ-⟪SpinOperators.act Y u,v⟫_ℂ‖≤
‖x-u‖*‖y‖+‖u‖*‖y-v‖ := by
have hY (w : SpinSpace E) : ‖SpinOperators.act Y w‖=‖w‖ :=
(SpinOperators.actEquiv Y Y_unitary).norm_map w
have he : ⟪SpinOperators.act Y x,y⟫_ℂ-⟪SpinOperators.act Y u,v⟫_ℂ=
⟪SpinOperators.act Y (x-u),y⟫_ℂ+⟪SpinOperators.act Y u,y-v⟫_ℂ := by
simp only [map_sub,inner_sub_left,inner_sub_right]
ring
rw [he]
apply (norm_add_le _ _).trans
simpa only [hY] using add_le_add (norm_inner_le_norm (𝕜 := ℂ) (SpinOperators.act Y (x-u)) y)
(norm_inner_le_norm (𝕜 := ℂ) (SpinOperators.act Y u) (y-v))
theorem huge_transverse_actual {α : Type*} {l : Filter α}
(U : α → SpinSpace E ≃ₗᵢ[ℂ] SpinSpace E) (Ω : SpinSpace E) (η : α → SpinSpace E)
(R : α → ℝ) (d e : α → E) (xp xm yp ym : α → PreSpin E)
(hR : Tendsto R l atTop) (B A δ C : ℝ) (hA : 0≤ A) (hδ : 0<δ)
(hxp : ∀ᶠ a in l, SpinRadiusLE (xp a) B ∧ spinMass (xp a)≤ A)
(hxm : ∀ᶠ a in l, SpinRadiusLE (xm a) B ∧ spinMass (xm a)≤ A)
(hyp : ∀ᶠ a in l, SpinRadiusLE (yp a) B ∧ spinMass (yp a)≤ A)
(hym : ∀ᶠ a in l, SpinRadiusLE (ym a) B ∧ spinMass (ym a)≤ A)
(hs : ∀ᶠ a in l, xp a 1=0 ∧ xm a 0=0 ∧ yp a 1=0 ∧ ym a 0=0)
(hsep : ∀ᶠ a in l, δ≤ ‖d a-e a‖) (hη : ∀ᶠ a in l, ‖η a‖≤ C)
(herrΩ : Tendsto (fun a => ‖U a Ω-hugePacket (R a) (d a) (e a) (xp a) (xm a)‖) l (𝓝 0))
(herrη : Tendsto (fun a => ‖U a (η a)-hugePacket (R a) (d a) (e a) (yp a) (ym a)‖) l (𝓝 0)) :
Tendsto (fun a => ⟪(U a).symm (SpinOperators.act Y (U a Ω)),η a⟫_ℂ) l (𝓝 0) := by
let P a := hugePacket (R a) (d a) (e a) (xp a) (xm a)
let Q a := hugePacket (R a) (d a) (e a) (yp a) (ym a)
have hp := tendsto_inner_rootY_hugePacket R d e xp xm yp ym hR B A δ hA hδ hxp hxm hyp hym hs hsep
have he : Tendsto (fun a =>
⟪SpinOperators.act Y (U a Ω),U a (η a)⟫_ℂ-⟪SpinOperators.act Y (P a),Q a⟫_ℂ) l (𝓝 0) := by
rw [tendsto_zero_iff_norm_tendsto_zero]
have hb := (herrΩ.mul_const C).add (herrη.const_mul (2*A))
simp only [zero_mul,mul_zero,add_zero] at hb
apply squeeze_zero' (Filter.Eventually.of_forall (fun _ => norm_nonneg _)) _ hb
filter_upwards [hxp,hxm,hη] with a hpa hma hηa
apply (inner_rootY_error_bound (U a Ω) (U a (η a)) (P a) (Q a)).trans
have hpn : ‖P a‖≤ 2*A := (norm_hugePacket_le _ _ _ _ _).trans (by linarith [hpa.2,hma.2])
rw [(U a).norm_map]
exact add_le_add (mul_le_mul_of_nonneg_left hηa (norm_nonneg _))
(mul_le_mul_of_nonneg_right hpn (norm_nonneg _))
have hh := he.add hp
simp only [P,Q,sub_add_cancel,add_zero] at hh
convert hh using 1
ext a
have hv := (U a).inner_map_map ((U a).symm (SpinOperators.act Y (U a Ω))) (η a)
simpa only [LinearIsometryEquiv.apply_symm_apply] using hv.symm
end CoherentFock
namespace GaussianCoherent
open MeasureTheory ProbabilityTheory Complex CoherentFock
open scoped BigOperators InnerProductSpace ComplexConjugate
variable {κ : Type*} [Fintype κ]
abbrev Mode (κ : Type*) [Fintype κ] := EuclideanSpace ℂ κ
abbrev Hilbert (κ : Type*) [Fintype κ] := Lp ℂ 2 (GaussianFourier.law κ)
def offset (d : Mode κ) : ℂ := (∑k, (d k)^2)/2-((‖d‖^2:ℝ):ℂ)/2
def wave (d : Mode κ) (g : κ → ℝ) : ℂ :=
Complex.exp (offset d)*Complex.exp (∑k, I*d k*(g k:ℂ))
theorem continuous_wave (d : Mode κ) : Continuous (wave d) := by
unfold wave
fun_prop
theorem wave_pair (d e : Mode κ) (g : κ → ℝ) :
conj (wave d g)*wave e g=
Complex.exp (conj (offset d)+offset e)*
Complex.exp (∑k, (I*(e k-conj (d k)))*(g k:ℂ)) := by
simp only [wave,map_mul,←Complex.exp_conj,map_sum,Complex.conj_I,Complex.conj_ofReal]
rw [←Complex.exp_add,←Complex.exp_add,←Complex.exp_add,←Complex.exp_add]
congr 1
have hh : (∑k, -I*conj (d k)*(g k:ℂ))+(∑k, I*e k*(g k:ℂ))=
∑k, I*(e k-conj (d k))*(g k:ℂ) := by
rw [←Finset.sum_add_distrib]
apply Finset.sum_congr rfl
intro k hk
ring
linear_combination hh
theorem integrable_wave_pair (d e : Mode κ) :
Integrable (fun g => conj (wave d g)*wave e g) (GaussianFourier.law κ) := by
simp_rw [wave_pair]
exact (GaussianFourier.integrable_exp_sum (fun k => I*(e k-conj (d k)))).const_mul _
theorem exponent_pair (d e : Mode κ) :
conj (offset d)+offset e+(∑k, (I*(e k-conj (d k)))^2/2)=
-((‖d‖^2+‖e‖^2:ℝ):ℂ)/2+⟪d,e⟫_ℂ := by
simp only [offset,map_sub,map_div₀,map_sum,map_pow,Complex.conj_ofReal,
map_ofNat,PiLp.inner_apply,RCLike.inner_apply']
push_cast
simp_rw [←Finset.sum_div]
have hs : (∑k, (conj (d k))^2)+(∑k, (e k)^2)+
(∑k, (I*(e k-conj (d k)))^2)=2*∑k, conj (d k)*e k := by
rw [←Finset.sum_add_distrib,←Finset.sum_add_distrib,Finset.mul_sum]
apply Finset.sum_congr rfl
intro k hk
ring_nf
rw [Complex.I_sq]
ring
linear_combination hs/2
theorem integral_wave_pair (d e : Mode κ) :
(∫g, conj (wave d g)*wave e g ∂GaussianFourier.law κ)=kernel d e := by
simp_rw [wave_pair]
rw [integral_const_mul,GaussianFourier.integral_exp_sum,←Complex.exp_add,exponent_pair]
unfold kernel
congr 1
push_cast
ring
theorem memLp_wave (d : Mode κ) : MemLp (wave d) 2 (GaussianFourier.law κ) := by
apply (memLp_two_iff_integrable_sq_norm (continuous_wave d).aestronglyMeasurable).mpr
have h := (integrable_wave_pair d d).re
convert h using 1
funext g
rw [Complex.conj_mul']
change ‖wave d g‖^2 = ((‖wave d g‖:ℂ)^2).re
rw [←Complex.ofReal_pow,Complex.ofReal_re]
def vector (d : Mode κ) : Hilbert κ := (memLp_wave d).toLp (wave d)
theorem vector_ae (d : Mode κ) : (vector d : (κ → ℝ) → ℂ)=ᵐ[GaussianFourier.law κ] wave d :=
(memLp_wave d).coeFn_toLp
@[simp] theorem inner_vector (d e : Mode κ) : ⟪vector d,vector e⟫_ℂ=kernel d e := by
rw [L2.inner_def]
rw [←integral_wave_pair d e]
apply integral_congr_ae
filter_upwards [vector_ae d,vector_ae e] with g hd he
rw [hd,he]
exact RCLike.inner_apply' _ _
def preMap : PreSpace (Mode κ) →ₗᵢ[ℂ] Hilbert κ :=
LinearMap.isometryOfInner
((Finsupp.linearCombination ℂ vector).comp toFinsupp.toLinearMap) (by
intro x y
change ⟪(toFinsupp x).sum (fun d a => a • vector d),
(toFinsupp y).sum (fun e b => b • vector e)⟫_ℂ=_
rw [Finsupp.sum_inner]
change (toFinsupp x).sum (fun d a => ⟪a • vector d,
(toFinsupp y).sum (fun e b => b • vector e)⟫_ℂ)=
(toFinsupp x).sum (fun d a => (toFinsupp y).sum (fun e b => conj a*kernel d e*b))
apply Finsupp.sum_congr
intro d hd
rw [Finsupp.inner_sum]
apply Finsupp.sum_congr
intro e he
simp only [inner_smul_left,inner_smul_right,inner_vector]
ring)
def representation : Space (Mode κ) →ₗᵢ[ℂ] Hilbert κ where
toLinearMap := preMap.toContinuousLinearMap.fromCompletion.toLinearMap
norm_map' x := by
refine UniformSpace.Completion.induction_on x
(isClosed_eq (preMap.toContinuousLinearMap.fromCompletion.continuous.norm) continuous_norm)
fun y => ?_
change ‖preMap.toContinuousLinearMap.fromCompletion (y:Space (Mode κ))‖=‖(y:Space (Mode κ))‖
rw [ContinuousLinearMap.fromCompletion_apply_coe,UniformSpace.Completion.norm_coe]
exact preMap.norm_map y
@[simp] theorem representation_coherent (d : Mode κ) : representation (coherent d)=vector d := by
change preMap.toContinuousLinearMap.fromCompletion
((toFinsupp.symm (Finsupp.single d 1):PreSpace (Mode κ)):Space (Mode κ))=vector d
rw [ContinuousLinearMap.fromCompletion_apply_coe]
change Finsupp.linearCombination ℂ vector (Finsupp.single d 1)=vector d
simp
end GaussianCoherent
namespace GaussianCoherent
open MeasureTheory ProbabilityTheory Complex CoherentFock
open scoped BigOperators InnerProductSpace ComplexConjugate
variable {κ : Type*} [Fintype κ]
def realMode (a : κ → ℝ) : Mode κ := WithLp.toLp 2 (fun k => (a k:ℂ))
@[simp] theorem realMode_apply (a : κ → ℝ) (k : κ) : realMode a k=(a k:ℂ) := rfl
@[simp] theorem norm_realMode_sq (a : κ → ℝ) : ‖realMode a‖^2=∑k, (a k)^2 := by
rw [EuclideanSpace.norm_sq_eq]
simp [Real.norm_eq_abs,sq_abs]
@[simp] theorem offset_realMode (a : κ → ℝ) : offset (realMode a)=0 := by
simp [offset,norm_realMode_sq,Complex.ofReal_sum]
@[simp] theorem wave_realMode (a : κ → ℝ) (g : κ → ℝ) :
wave (realMode a) g=Complex.exp ((∑k, a k*g k:ℝ)*I) := by
simp only [wave,offset_realMode,Complex.exp_zero,one_mul,realMode_apply]
congr 1
push_cast
rw [Finset.sum_mul]
apply Finset.sum_congr rfl
intro k hk
ring
@[simp] theorem norm_wave_realMode (a : κ → ℝ) (g : κ → ℝ) : ‖wave (realMode a) g‖=1 := by
rw [wave_realMode,Complex.norm_exp]
simp
theorem memLp_seedPhase (a : κ → ℝ) (f : Hilbert κ) :
MemLp (fun g => wave (realMode a) g*f g) 2 (GaussianFourier.law κ) := by
apply (Lp.memLp f).congr_norm
((continuous_wave (realMode a)).aestronglyMeasurable.mul (Lp.aestronglyMeasurable f))
exact Filter.Eventually.of_forall fun g => by
change ‖f g‖=‖wave (realMode a) g*f g‖
rw [norm_mul,norm_wave_realMode,one_mul]
def seedPhase (a : κ → ℝ) (f : Hilbert κ) : Hilbert κ :=
(memLp_seedPhase a f).toLp (fun g => wave (realMode a) g*f g)
theorem seedPhase_ae (a : κ → ℝ) (f : Hilbert κ) :
(seedPhase a f : (κ → ℝ) → ℂ)=ᵐ[GaussianFourier.law κ] fun g => wave (realMode a) g*f g :=
MemLp.coeFn_toLp _
def seedPhaseIsometry (a : κ → ℝ) : Hilbert κ →ₗᵢ[ℂ] Hilbert κ where
toFun := seedPhase a
map_add' f h := by
apply Lp.ext
filter_upwards [seedPhase_ae a (f+h),Lp.coeFn_add f h,
Lp.coeFn_add (seedPhase a f) (seedPhase a h),seedPhase_ae a f,seedPhase_ae a h] with g h1 h2 h3 h4 h5
rw [h1,h2,h3]
simp only [Pi.add_apply,h4,h5]
exact mul_add _ _ _
map_smul' c f := by
change seedPhase a (c • f)=c • seedPhase a f
apply Lp.ext
filter_upwards [seedPhase_ae a (c • f),Lp.coeFn_smul c f,
Lp.coeFn_smul c (seedPhase a f),seedPhase_ae a f] with g h1 h2 h3 h4
rw [h1,h2,h3]
simp only [Pi.smul_apply,h4]
simp only [smul_eq_mul]
ring
norm_map' f := by
have hh : ∀ᵐ g ∂GaussianFourier.law κ, ‖seedPhase a f g‖=‖f g‖ := by
filter_upwards [seedPhase_ae a f] with g hg
rw [hg,norm_mul,norm_wave_realMode,one_mul]
exact le_antisymm (Lp.norm_le_norm_of_ae_le (hh.mono fun _ h => h.le))
(Lp.norm_le_norm_of_ae_le (hh.mono fun _ h => h.ge))
theorem offset_real_add (a : κ → ℝ) (d : Mode κ) :
offset (realMode a+d)=offset d+((⟪realMode a,d⟫_ℂ).im:ℂ)*I := by
have hs : (∑k, (realMode a k+d k)^2)=
(∑k, (realMode a k)^2)+2*⟪realMode a,d⟫_ℂ+(∑k, (d k)^2) := by
simp only [PiLp.inner_apply,RCLike.inner_apply',realMode_apply,Complex.conj_ofReal]
rw [Finset.mul_sum,←Finset.sum_add_distrib,←Finset.sum_add_distrib]
apply Finset.sum_congr rfl
intro k hk
ring
have ho := offset_realMode a
unfold offset at ho ⊢
simp only [PiLp.add_apply]
rw [_root_.norm_add_sq (𝕜 := ℂ)]
rw [hs]
have hc := Complex.re_add_im ⟪realMode a,d⟫_ℂ
push_cast at ho ⊢
linear_combination ho - hc
theorem phase_wave_real_add (a : κ → ℝ) (d : Mode κ) (g : κ → ℝ) :
phase (realMode a) d*wave (realMode a+d) g=wave (realMode a) g*wave d g := by
simp only [phase,wave,offset_realMode,Complex.exp_zero,one_mul,offset_real_add]
simp only [←Complex.exp_add]
congr 1
simp only [PiLp.add_apply,mul_add,add_mul,Finset.sum_add_distrib]
push_cast
ring
theorem seedPhase_vector (a : κ → ℝ) (d : Mode κ) :
seedPhaseIsometry a (vector d)=phase (realMode a) d • vector (realMode a+d) := by
apply Lp.ext
filter_upwards [seedPhase_ae a (vector d),vector_ae d,vector_ae (realMode a+d),
Lp.coeFn_smul (phase (realMode a) d) (vector (realMode a+d))] with g h1 h2 h3 h4
change seedPhase a (vector d) g = _
rw [h1,h2,h4]
simp only [Pi.smul_apply,smul_eq_mul]
rw [h3]
exact (phase_wave_real_add a d g).symm
theorem representation_W_real (a : κ → ℝ) (x : Space (Mode κ)) :
representation (W (realMode a) x)=seedPhaseIsometry a (representation x) := by
have he : representation.toContinuousLinearMap.comp (W (realMode a))=
(seedPhaseIsometry a).toContinuousLinearMap.comp representation.toContinuousLinearMap := by
apply CoherentFock.ext_coherent
intro d
simp only [ContinuousLinearMap.comp_apply,LinearIsometry.coe_toContinuousLinearMap,
W_coherent,map_smul,representation_coherent,seedPhase_vector]
exact DFunLike.congr_fun he x
end GaussianCoherent
namespace FourierDensity
open MeasureTheory ProbabilityTheory Complex
open scoped BigOperators ComplexConjugate InnerProductSpace
variable {κ : Type*} [Fintype κ]
def character (a g : κ → ℝ) : ℂ := Complex.exp ((∑k, a k*g k:ℝ)*I)
theorem continuous_character (a : κ → ℝ) : Continuous (character a) := by
unfold character
fun_prop
@[simp] theorem norm_character (a g : κ → ℝ) : ‖character a g‖=1 := by
simp [character,Complex.norm_exp]
@[simp] theorem character_neg (a g : κ → ℝ) : character (-a) g=conj (character a g) := by
simp [character,←Complex.exp_conj,Finset.sum_neg_distrib]
variable {μ : Measure (κ → ℝ)}
theorem integrable_character_mul {f : (κ → ℝ) → ℂ}
(hf : Integrable f μ) (a : κ → ℝ) : Integrable (fun g => character a g*f g) μ :=
hf.bdd_mul (continuous_character a).aestronglyMeasurable
(Filter.Eventually.of_forall fun g => (norm_character a g).le)
theorem dual_eq_sum [DecidableEq κ] (L : StrongDual ℝ (κ → ℝ)) (g : κ → ℝ) :
L g=∑k, L (Pi.single k 1)*g k := by
classical
have hg : g=∑k, g k • Pi.single k 1 := by
ext j
simp [Finset.sum_apply,Pi.smul_apply,Pi.single_apply]
conv_lhs => rw [hg]
simp only [map_sum,map_smul,smul_eq_mul,mul_comm]
theorem ae_zero_of_real_fourier_zero [IsFiniteMeasure μ]
{f : (κ → ℝ) → ℝ} (hf : Integrable f μ)
(hF : ∀a, (∫g, character a g*(f g:ℂ) ∂μ)=0) : f=ᵐ[μ] 0 := by
classical
let fpos := fun g => max (f g) 0
let fneg := fun g => max (-f g) 0
have hp : Integrable fpos μ := hf.pos_part
have hn : Integrable fneg μ := hf.neg_part
let μp := μ.withDensity (fun g => ENNReal.ofReal (fpos g))
let μn := μ.withDensity (fun g => ENNReal.ofReal (fneg g))
have : IsFiniteMeasure μp := isFiniteMeasure_withDensity_ofReal hp.2
have : IsFiniteMeasure μn := isFiniteMeasure_withDensity_ofReal hn.2
have heq : μp=μn := by
apply Measure.ext_of_charFunDual
funext L
simp only [charFunDual_apply]
have hl : (fun g => Complex.exp ((L g : ℝ)*I))=
character (fun k => L (Pi.single k 1)) := by
funext g
rw [dual_eq_sum L g]
rfl
rw [hl]
change (∫g, character (fun k => L (Pi.single k 1)) g ∂μp)=
(∫g, character (fun k => L (Pi.single k 1)) g ∂μn)
dsimp only [μp,μn]
rw [integral_withDensity_eq_integral_toReal_smul₀ hp.1.aemeasurable.ennreal_ofReal
(Filter.Eventually.of_forall fun _ => ENNReal.ofReal_lt_top),
integral_withDensity_eq_integral_toReal_smul₀ hn.1.aemeasurable.ennreal_ofReal
(Filter.Eventually.of_forall fun _ => ENNReal.ofReal_lt_top)]
simp only [ENNReal.toReal_ofReal (le_max_right _ _),fpos,fneg,real_smul]
apply sub_eq_zero.mp
change (∫g, (fpos g:ℂ)*character (fun k => L (Pi.single k 1)) g ∂μ)-
(∫g, (fneg g:ℂ)*character (fun k => L (Pi.single k 1)) g ∂μ)=0
have hpC : Integrable (fun g => (fpos g:ℂ)*character
(fun k => L (Pi.single k 1)) g) μ :=
(integrable_character_mul hp.ofReal (fun k => L (Pi.single k 1))).congr
(Filter.Eventually.of_forall fun g => mul_comm _ _)
have hnC : Integrable (fun g => (fneg g:ℂ)*character
(fun k => L (Pi.single k 1)) g) μ :=
(integrable_character_mul hn.ofReal (fun k => L (Pi.single k 1))).congr
(Filter.Eventually.of_forall fun g => mul_comm _ _)
rw [←integral_sub hpC hnC]
convert hF (fun k => L (Pi.single k 1)) using 1
congr 1
funext g
have hm : max (f g) 0-max (-f g) 0=f g := max_zero_sub_max_neg_zero_eq_self _
dsimp only [fpos,fneg]
rw [←sub_mul,←Complex.ofReal_sub,hm,mul_comm]
have hd := (withDensity_eq_iff_of_sigmaFinite hp.1.aemeasurable.ennreal_ofReal
hn.1.aemeasurable.ennreal_ofReal).mp heq
filter_upwards [hd] with g hg
have hh := congrArg ENNReal.toReal hg
simp only [ENNReal.toReal_ofReal (le_max_right _ _),fpos,fneg] at hh
change f g=0
have hm : max (f g) 0-max (-f g) 0=f g := max_zero_sub_max_neg_zero_eq_self _
linarith
theorem ae_re_zero_of_fourier_zero [IsFiniteMeasure μ]
{f : (κ → ℝ) → ℂ} (hf : Integrable f μ)
(hF : ∀a, (∫g, character a g*f g ∂μ)=0) :
(fun g => (f g).re)=ᵐ[μ] 0 := by
have hc : ∀a, (∫g, character a g*conj (f g) ∂μ)=0 := by
intro a
have hh := congrArg conj (hF (-a))
rw [map_zero,←integral_conj] at hh
simpa only [map_mul,character_neg,Complex.conj_conj] using hh
have hfc : Integrable (fun g => conj (f g)) μ :=
(@RCLike.conjLIE ℂ _).toContinuousLinearEquiv.toContinuousLinearMap.integrable_comp hf
apply ae_zero_of_real_fourier_zero hf.re
intro a
calc
(∫g, character a g*((f g).re:ℂ) ∂μ)=
(1/2:ℂ)*(∫g, character a g*f g+character a g*conj (f g) ∂μ) := by
rw [←integral_const_mul]
apply integral_congr_ae
exact Filter.Eventually.of_forall fun g => by
have hadd := Complex.add_conj (f g)
push_cast at hadd
linear_combination -(character a g)*hadd/2
_=0 := by
rw [integral_add (integrable_character_mul hf a) (integrable_character_mul hfc a),
hF a,hc a]
simp
theorem ae_zero_of_fourier_zero [IsFiniteMeasure μ]
{f : (κ → ℝ) → ℂ} (hf : Integrable f μ)
(hF : ∀a, (∫g, character a g*f g ∂μ)=0) : f=ᵐ[μ] 0 := by
have hr := ae_re_zero_of_fourier_zero hf hF
have hi := ae_re_zero_of_fourier_zero (hf.const_mul I) (fun a => by
calc
(∫g, character a g*(I*f g) ∂μ)=I*(∫g, character a g*f g ∂μ) := by
rw [←integral_const_mul]
congr 1
funext g
ring
_=0 := by rw [hF a,mul_zero])
filter_upwards [hr,hi] with g hrg hig
apply Complex.ext
· exact hrg
· simpa using hig
end FourierDensity
namespace GaussianCoherent
open MeasureTheory ProbabilityTheory Complex CoherentFock
open scoped BigOperators InnerProductSpace ComplexConjugate
variable {κ : Type*} [Fintype κ]
theorem representation_surjective : Function.Surjective (representation (κ := κ)) := by
let K := (representation (κ := κ)).toLinearMap.range
have hK : IsClosed (K : Set (Hilbert κ)) :=
(representation (κ := κ)).isometry.isClosedEmbedding.isClosed_range
have hbot : Kᗮ=⊥ := by
apply (Submodule.eq_bot_iff _).mpr
intro f hf
apply Lp.ext
have hi : Integrable (fun g => f g) (GaussianFourier.law κ) :=
memLp_one_iff_integrable.mp ((Lp.memLp f).mono_exponent (by norm_num))
have hF : ∀a, (∫g, FourierDensity.character a g*f g ∂GaussianFourier.law κ)=0 := by
intro a
have hh := (Submodule.mem_orthogonal K f).mp hf (vector (realMode (-a)))
⟨coherent (realMode (-a)),representation_coherent _⟩
rw [L2.inner_def] at hh
convert hh using 1
apply integral_congr_ae
filter_upwards [vector_ae (realMode (-a))] with g hg
rw [RCLike.inner_apply',hg,wave_realMode]
change FourierDensity.character a g*f g=
conj (FourierDensity.character (-a) g)*f g
rw [FourierDensity.character_neg,Complex.conj_conj]
have hz := FourierDensity.ae_zero_of_fourier_zero hi hF
exact hz.trans (Lp.coeFn_zero ℂ 2 (GaussianFourier.law κ)).symm
apply LinearMap.range_eq_top.mp
change K=⊤
calc
K=K.topologicalClosure := hK.submodule_topologicalClosure_eq.symm
_=Kᗮᗮ := (Submodule.orthogonal_orthogonal_eq_closure K).symm
_=⊤ := by rw [hbot,Submodule.bot_orthogonal_eq_top]
def gaussianUnitary : Space (Mode κ) ≃ₗᵢ[ℂ] Hilbert κ :=
LinearIsometryEquiv.ofSurjective representation representation_surjective
@[simp] theorem gaussianUnitary_coherent (d : Mode κ) :
gaussianUnitary (coherent d)=vector d := representation_coherent d
theorem gaussianUnitary_W_real (a : κ → ℝ) (x : Space (Mode κ)) :
gaussianUnitary (W (realMode a) x)=seedPhaseIsometry a (gaussianUnitary x) :=
representation_W_real a x
end GaussianCoherent
namespace CoherentFock
open scoped InnerProductSpace ComplexConjugate
variable {E : Type*} [NormedAddCommGroup E] [InnerProductSpace ℂ E]
theorem eq_zero_of_inner_coherent (x : Space E) (hx : ∀d, ⟪coherent d,x⟫_ℂ=0) : x=0 := by
have hh : innerSL ℂ x=0 := by
apply ext_coherent
intro d
exact inner_eq_zero_symm.mp (hx d)
have hhx := DFunLike.congr_fun hh x
exact inner_self_eq_zero.mp hhx
end CoherentFock
end
end OAI