File size: 8,677 Bytes
159357f
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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
import Mathlib
import OAI.Analysis.Conductivity.Sources.WeightedSpectralSpace

namespace OAI

noncomputable section
namespace ScalarConductivity
open Set MeasureTheory Filter Topology
open scoped ENNReal

def spectralGraphWeight {ι : Type*} (w : ι → ℝ) :
    spectralTraceGraph w →L[ℝ] SpectralL2 ι :=
  ((PiLp.proj 2 (fun _ : Fin 2 => SpectralL2 ι) 1).comp
    (spectralTraceGraph w).subtypeL).restrictScalars ℝ

def spectralGraphMean {ι : Type*} [Zero ι] (w : ι → ℝ) :
    spectralTraceGraph w →L[ℝ] ℝ :=
  Complex.reCLM.comp (((lp.evalCLM ℂ (fun _ : ι => ℂ) 2 0).comp
    ((PiLp.proj 2 (fun _ : Fin 2 => SpectralL2 ι) 0).comp
      (spectralTraceGraph w).subtypeL)).restrictScalars ℝ)

variable {V G : Type*} [NormedAddCommGroup V] [InnerProductSpace ℝ V]
  [NormedAddCommGroup G] [InnerProductSpace ℝ G]

def centralForm {ι : Type*} (w : ι → ℝ) (D : V →L[ℝ] G)
    (T : Fin 3 → V →L[ℝ] spectralTraceGraph w) : V →L[ℝ] V →L[ℝ] ℝ :=
  (((innerSL ℝ).comp D).flip.comp D).flip + ∑ i : Fin 3,
    (((innerSL ℝ).comp ((spectralGraphWeight w).comp (T i))).flip.comp
      ((spectralGraphWeight w).comp (T i))).flip

lemma centralForm_apply {ι : Type*} (w : ι → ℝ) (D : V →L[ℝ] G)
    (T : Fin 3 → V →L[ℝ] spectralTraceGraph w) (u v : V) :
    centralForm w D T u v=inner ℝ (D u) (D v)+
      ∑ i : Fin 3,inner ℝ (spectralGraphWeight w (T i u)) (spectralGraphWeight w (T i v)) := by
  simp [centralForm]

lemma centralForm_lower {ι : Type*} (w : ι → ℝ) (D : V →L[ℝ] G)
    (T : Fin 3 → V →L[ℝ] spectralTraceGraph w) (u : V) :
    ‖D u‖^2≤centralForm w D T u u := by
  rw [centralForm_apply,real_inner_self_eq_norm_sq]
  exact le_add_of_nonneg_right (Finset.sum_nonneg fun i _ => real_inner_self_nonneg)

theorem solve_form_mod_constants [CompleteSpace V]
    (B : V →L[ℝ] V →L[ℝ] ℝ) (M F : V →L[ℝ] ℝ) (oneV : V)
    (hM : M oneV=1) (hF : F oneV=0)
    (hB : ∀ u : V,B u oneV=0) (hB' : ∀ v : V,B oneV v=0)
    (hcoer : IsCoercive (((B.comp M.ker.subtypeL).flip.comp M.ker.subtypeL).flip)) :
    ∃ p : V, M p=0 ∧ (∀ v : V,B p v=F v) ∧
      (∀ q : V,(∀ v : V,B q v=F v) → q-p=M q • oneV) := by
  let K := M.ker
  have hclosed : IsClosed (K : Set V) := M.isClosed_ker
  let : CompleteSpace K := hclosed.completeSpace_coe
  let A : K →L[ℝ] K →L[ℝ] ℝ := ((B.comp K.subtypeL).flip.comp K.subtypeL).flip
  let L : K →L[ℝ] ℝ := F.comp K.subtypeL
  let p : K := hcoer.continuousLinearEquivOfBilin.symm ((InnerProductSpace.toDual ℝ K).symm L)
  have hp (v : K) : B p.val v.val=F v.val := by
    change A p v=L v
    rw [←hcoer.continuousLinearEquivOfBilin_apply]
    dsimp only [p]
    rw [hcoer.continuousLinearEquivOfBilin.apply_symm_apply]
    exact congrArg (fun f : K →L[ℝ] ℝ => f v) ((InnerProductSpace.toDual ℝ K).apply_symm_apply L)
  have hpM : M p.val=0 := p.property
  have hfull (v : V) : B p.val v=F v := by
    have hv : v-M v • oneV∈K := by
      change M (v-M v • oneV)=0
      simp [hM]
    have hh := hp ⟨_,hv⟩
    change B p.val (v-M v • oneV)=F (v-M v • oneV) at hh
    simpa only [map_sub,map_smul,hB,hF,smul_zero,sub_zero] using hh
  refine ⟨p.val,hpM,hfull,?_⟩
  intro q hq
  let d : V := q-p.val-M q • oneV
  have hdK : d∈K := by
    change M (q-p.val-M q • oneV)=0
    simp [hpM,hM]
  have hd : B d d=0 := by
    dsimp only [d]
    simp only [map_sub,map_smul,sub_apply,smul_apply,
      hq,hfull,hB',smul_zero,sub_self]
  have hz : (⟨d,hdK⟩ : K)=0 := by
    apply hcoer.continuousLinearEquivOfBilin.injective
    apply ext_inner_right ℝ
    intro v
    rw [map_zero,inner_zero_left,hcoer.continuousLinearEquivOfBilin_apply]
    change B d v.val=0
    dsimp only [d]
    simp only [map_sub,map_smul,sub_apply,smul_apply,
      hq,hfull,hB',smul_zero,sub_self]
  have he : d=0 := congrArg (fun z : K => z.val) hz
  exact sub_eq_zero.mp he

theorem central_variational_exists [CompleteSpace V] {ι : Type*} [Zero ι]
    (w : ι → ℝ) (D : V →L[ℝ] G) (T : Fin 3 → V →L[ℝ] spectralTraceGraph w)
    (M : V →L[ℝ] ℝ) (oneV : V) (hM : M oneV=1) (hD : D oneV=0)
    (hT : ∀ i,spectralGraphWeight w (T i oneV)=0)
    (havg : ∀ i,spectralGraphMean w (T i oneV)=1)
    {C : ℝ} (hC : 0<C) (hP : ∀ u : M.ker,‖u‖≤C*‖D u.val‖)
    (s : Fin 3 → ℝ) (hs : ∑ i,s i=0) :
    ∃ p : V,M p=0 ∧
      (∀ v : V,inner ℝ (D p) (D v)+
        (∑ i : Fin 3,inner ℝ (spectralGraphWeight w (T i p))
          (spectralGraphWeight w (T i v)))=
        ∑ i : Fin 3,s i*spectralGraphMean w (T i v)) ∧
      (∀ q : V,(∀ v : V,centralForm w D T q v=
        ∑ i : Fin 3,s i*spectralGraphMean w (T i v)) → q-p=M q • oneV) := by
  let B := centralForm w D T
  let F : V →L[ℝ] ℝ := ∑ i : Fin 3,s i • (spectralGraphMean w).comp (T i)
  have hFa (v : V) : F v=∑ i : Fin 3,s i*spectralGraphMean w (T i v) := by
    simp [F,smul_eq_mul]
  have hF : F oneV=0 := by rw [hFa]; simpa only [havg,mul_one] using hs
  have hB (u : V) : B u oneV=0 := by
    simp only [B,centralForm_apply,hD,inner_zero_right,hT,Finset.sum_const_zero,add_zero]
  have hB' (v : V) : B oneV v=0 := by
    simp only [B,centralForm_apply,hD,inner_zero_left,hT,Finset.sum_const_zero,zero_add]
  have hcoer : IsCoercive (((B.comp M.ker.subtypeL).flip.comp M.ker.subtypeL).flip) := by
    refine ⟨C⁻¹^2,sq_pos_of_pos (inv_pos.mpr hC),?_⟩
    intro u
    change C⁻¹^2*‖u‖*‖u‖≤B u.val u.val
    have hh := mul_self_le_mul_self (norm_nonneg u) (hP u)
    have hlo := centralForm_lower w D T u.val
    have hCC : 0<C^2 := sq_pos_of_pos hC
    have hb : ‖u‖^2/C^2≤‖D u.val‖^2 := by
      apply (div_le_iff₀ hCC).mpr
      nlinarith [hh]
    calc
      _=‖u‖^2/C^2 := by simp only [div_eq_mul_inv,inv_pow]; ring
      _≤‖D u.val‖^2 := hb
      _≤B u.val u.val := hlo
  obtain ⟨p,hp,hfull,huniq⟩ := solve_form_mod_constants B M F oneV hM hF hB hB' hcoer
  refine ⟨p,hp,?_,?_⟩
  · intro v
    exact (centralForm_apply w D T p v).symm.trans ((hfull v).trans (hFa v))
  · intro q hq
    apply huniq q
    intro v
    exact (hq v).trans (hFa v).symm

theorem central_variational_exists_graph [CompleteSpace V] {ι : Type*} [Zero ι]
    (w : ι → ℝ) (D : V →L[ℝ] G) (T : Fin 3 → V →L[ℝ] spectralTraceGraph w)
    (M : V →L[ℝ] ℝ) (oneV : V) (hM : M oneV=1) (hD : D oneV=0)
    (hT : ∀ i,spectralGraphWeight w (T i oneV)=0)
    (havg : ∀ i,spectralGraphMean w (T i oneV)=1)
    {C : ℝ} (hC : 0<C)
    (hP : ∀ u : M.ker,‖u‖^2≤C*(‖D u.val‖^2+
      ∑ i : Fin 3,‖spectralGraphWeight w (T i u.val)‖^2))
    (s : Fin 3 → ℝ) (hs : ∑ i,s i=0) :
    ∃ p : V,M p=0 ∧
      (∀ v : V,inner ℝ (D p) (D v)+
        (∑ i : Fin 3,inner ℝ (spectralGraphWeight w (T i p))
          (spectralGraphWeight w (T i v)))=
        ∑ i : Fin 3,s i*spectralGraphMean w (T i v)) ∧
      (∀ q : V,(∀ v : V,inner ℝ (D q) (D v)+
        (∑ i : Fin 3,inner ℝ (spectralGraphWeight w (T i q))
          (spectralGraphWeight w (T i v)))=
        ∑ i : Fin 3,s i*spectralGraphMean w (T i v)) → q-p=M q • oneV) := by
  let B := centralForm w D T
  let F : V →L[ℝ] ℝ := ∑ i : Fin 3,s i • (spectralGraphMean w).comp (T i)
  have hFa (v : V) : F v=∑ i : Fin 3,s i*spectralGraphMean w (T i v) := by
    simp [F,smul_eq_mul]
  have hF : F oneV=0 := by rw [hFa]; simpa only [havg,mul_one] using hs
  have hB (u : V) : B u oneV=0 := by
    simp only [B,centralForm_apply,hD,inner_zero_right,hT,Finset.sum_const_zero,add_zero]
  have hB' (v : V) : B oneV v=0 := by
    simp only [B,centralForm_apply,hD,inner_zero_left,hT,Finset.sum_const_zero,zero_add]
  have hcoer : IsCoercive (((B.comp M.ker.subtypeL).flip.comp M.ker.subtypeL).flip) := by
    refine ⟨C⁻¹,inv_pos.mpr hC,?_⟩
    intro u
    change C⁻¹*‖u‖*‖u‖≤B u.val u.val
    have hh := hP u
    have he : B u.val u.val=‖D u.val‖^2+
        ∑ i : Fin 3,‖spectralGraphWeight w (T i u.val)‖^2 := by
      simp only [B,centralForm_apply,real_inner_self_eq_norm_sq]
    rw [←he] at hh
    calc
      _=‖u‖^2/C := by ring
      _≤B u.val u.val := (div_le_iff₀ hC).mpr (by simpa only [mul_comm] using hh)
  obtain ⟨p,hp,hfull,huniq⟩ := solve_form_mod_constants B M F oneV hM hF hB hB' hcoer
  refine ⟨p,hp,?_,?_⟩
  · intro v
    exact (centralForm_apply w D T p v).symm.trans ((hfull v).trans (hFa v))
  · intro q hq
    apply huniq q
    intro v
    exact (centralForm_apply w D T q v).trans ((hq v).trans (hFa v).symm)

end ScalarConductivity

end

end OAI