File size: 6,748 Bytes
9eeb9c7
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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
import OAI.Analysis.InterpolatedFactors.Scaling

namespace OAI

noncomputable section

universe u_1 u_2 u_3 u_4 u_5

namespace FreeGroupFactorMain.Amplification

section
variable {A : Type u_1} {B : Type u_2} {C : Type u_3} [CStarAlgebra A] [CStarAlgebra B] [CStarAlgebra C]

namespace NormalTracialEquiv
variable {τA : A → ℂ} {τB : B → ℂ} {τC : C → ℂ}
variable {𝒯A : TopologicalSpace A} {𝒯B : TopologicalSpace B} {𝒯C : TopologicalSpace C}

def symm (e : NormalTracialEquiv τA τB 𝒯A 𝒯B) : NormalTracialEquiv τB τA 𝒯B 𝒯A where
  equiv := e.equiv.symm
  trace_eq x := by simpa only [StarAlgEquiv.apply_symm_apply] using (e.trace_eq (e.equiv.symm x)).symm
  normal := e.inverse_normal
  inverse_normal := e.normal

def trans (e : NormalTracialEquiv τA τB 𝒯A 𝒯B) (f : NormalTracialEquiv τB τC 𝒯B 𝒯C) :
    NormalTracialEquiv τA τC 𝒯A 𝒯C where
  equiv := e.equiv.trans f.equiv
  trace_eq x := (f.trace_eq (e.equiv x)).trans (e.trace_eq x)
  normal := by
    let : TopologicalSpace A := 𝒯A
    let : TopologicalSpace B := 𝒯B
    let : TopologicalSpace C := 𝒯C
    exact f.normal.comp e.normal
  inverse_normal := by
    let : TopologicalSpace A := 𝒯A
    let : TopologicalSpace B := 𝒯B
    let : TopologicalSpace C := 𝒯C
    exact e.inverse_normal.comp f.inverse_normal

end NormalTracialEquiv
end

open scoped ENNReal
variable {G : Type u_4} [Group G]

abbrev GroupCornerNormalIso (t : ℝ) (p : stabilization G) (hp : IsStarProjection p) :=
  NormalTracialEquiv (normalizedCornerTrace stabilizedTrace t p hp) canonicalTrace
    (cornerTopology (stabilizationTopology G) p hp) (groupUltraweakTopology G)

def unitNormalIso {A : Type u_5} [CStarAlgebra A] (τ : A → ℂ) (𝒯 : TopologicalSpace A) :
    NormalTracialEquiv (fun x : Corner (1:A) (IsStarProjection.one A) => τ x.val) τ
      (cornerTopology 𝒯 1 (IsStarProjection.one A)) 𝒯 where
  equiv := unitCornerEquiv.symm
  trace_eq _ := rfl
  normal := by
    let : TopologicalSpace A := 𝒯
    exact continuous_subtype_val
  inverse_normal := by
    let : TopologicalSpace A := 𝒯
    exact continuous_id.subtype_mk _

def finiteSingletonNormalIso (p : groupVonNeumann G) (hp : IsStarProjection p) :
    NormalTracialEquiv (normalizedCornerTrace stabilizedTrace 1 (finiteProjection 1 p)
      (finiteProjection_projection 1 p hp)) (fun x : Corner p hp => canonicalTrace x.val)
      (cornerTopology (stabilizationTopology G) (finiteProjection 1 p) (finiteProjection_projection 1 p hp))
      (cornerTopology (groupUltraweakTopology G) p hp) where
  equiv := finiteCornerSingletonIso p hp
  trace_eq x := by
    simp only [normalizedCornerTrace,Complex.ofReal_one,inv_one,one_mul]
    exact finiteCornerSingletonIso_trace p hp x
  normal := finiteCornerSingletonIso_normal p hp
  inverse_normal := finiteCornerSingletonIso_symm_normal p hp

def finiteUnitCornerIso : GroupCornerNormalIso (G := G) 1
    (finiteProjection 1 (1 : groupVonNeumann G)) (finiteProjection_projection 1 1 (IsStarProjection.one _)) :=
  (finiteSingletonNormalIso (1 : groupVonNeumann G) (IsStarProjection.one _)).trans
    (unitNormalIso canonicalTrace (groupUltraweakTopology G))

theorem canonicalTrace_one : canonicalTrace (1 : groupVonNeumann G)=1 := by
  classical
  simp [canonicalTrace,lp.single_apply]

theorem finiteUnitProjection_trace :
    stabilizedProjectionTrace (finiteProjection 1 (1 : groupVonNeumann G))=ENNReal.ofReal 1 := by
  rw [finiteProjection_trace 1 1 (IsStarProjection.one _) 1 zero_le_one canonicalTrace_one]
  norm_num

theorem preferred_unit_iso
    (hbase : ∀ T : groupVonNeumann G, (∀ S : groupVonNeumann G,Commute T S) →
      ∃ c : ℂ,T=c • (1 : groupVonNeumann G))
    (p : stabilization G) (hp : IsStarProjection p) (hptr : stabilizedProjectionTrace p=ENNReal.ofReal 1) :
    Nonempty (GroupCornerNormalIso 1 p hp) := by
  obtain ⟨e,heτ,hen,hein⟩ := finite_corner_choice_both (G := G) hbase 1 p
    (finiteProjection 1 (1 : groupVonNeumann G)) hp (finiteProjection_projection 1 1 (IsStarProjection.one _))
    (hptr.trans finiteUnitProjection_trace.symm) (hptr ▸ ENNReal.ofReal_ne_top)
  let E : NormalTracialEquiv (normalizedCornerTrace stabilizedTrace 1 p hp)
      (normalizedCornerTrace stabilizedTrace 1 (finiteProjection 1 (1 : groupVonNeumann G))
        (finiteProjection_projection 1 1 (IsStarProjection.one _)))
      (cornerTopology (stabilizationTopology G) p hp)
      (cornerTopology (stabilizationTopology G) (finiteProjection 1 (1 : groupVonNeumann G))
        (finiteProjection_projection 1 1 (IsStarProjection.one _))) := ⟨e,heτ,hen,hein⟩
  exact ⟨E.trans finiteUnitCornerIso⟩

theorem scaling_ratio_trace (t : ℝ) (ht : 0<t) (n : ℕ) (_hn : 0<(n:ℝ))
    (q r : groupVonNeumann G) (hq : IsStarProjection q) (hr : IsStarProjection r)
    (f : groupVonNeumann G ≃⋆ₐ[ℂ] Corner q hq) (g : groupVonNeumann G ≃⋆ₐ[ℂ] Corner r hr)
    (hf : ∀ x,canonicalTrace (f x).val=((t/(n:ℝ):ℝ):ℂ)*canonicalTrace x)
    (hg : ∀ x,canonicalTrace (g x).val=((1/(n:ℝ):ℝ):ℂ)*canonicalTrace x)
    (x : Corner q hq) : canonicalTrace (g (f.symm x)).val=(t:ℂ)⁻¹*canonicalTrace x.val := by
  have hh := hf (f.symm x)
  rw [StarAlgEquiv.apply_symm_apply] at hh
  rw [hg,hh]
  push_cast
  field_simp [Complex.ofReal_ne_zero.mpr ht.ne']

 def finiteScaledIso (n : ℕ) (t : ℝ)
    (q r : groupVonNeumann G) (hq : IsStarProjection q) (hr : IsStarProjection r)
    (e : Corner q hq ≃⋆ₐ[ℂ] Corner r hr)
    (heτ : ∀x,canonicalTrace (e x).val=(t:ℂ)⁻¹*canonicalTrace x.val)
    (hen : @Continuous _ _ (cornerTopology (groupUltraweakTopology G) q hq)
      (cornerTopology (groupUltraweakTopology G) r hr) e)
    (hein : @Continuous _ _ (cornerTopology (groupUltraweakTopology G) r hr)
      (cornerTopology (groupUltraweakTopology G) q hq) e.symm) :
    NormalTracialEquiv (normalizedCornerTrace stabilizedTrace t (finiteProjection n q) (finiteProjection_projection n q hq))
      (normalizedCornerTrace stabilizedTrace 1 (finiteProjection n r) (finiteProjection_projection n r hr))
      (cornerTopology (stabilizationTopology G) (finiteProjection n q) (finiteProjection_projection n q hq))
      (cornerTopology (stabilizationTopology G) (finiteProjection n r) (finiteProjection_projection n r hr)) where
  equiv := finiteCornerIso n q hq r hr e
  trace_eq x := by
    simp only [normalizedCornerTrace,Complex.ofReal_one,inv_one,one_mul]
    exact finiteCornerIso_trace n q hq r hr e (t:ℂ)⁻¹ heτ x
  normal := finiteCornerIso_normal n q hq r hr e hen
  inverse_normal := by
    rw [finiteCornerIso_symm]
    exact finiteCornerIso_normal n r hr q hq e.symm hein

end FreeGroupFactorMain.Amplification

end

end OAI