File size: 5,619 Bytes
b317718
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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
import OAI.Probability.FreeIsing.Estimates.FairSpin
import OAI.Probability.FreeIsing.Estimates.MeasurableConnectivity
import OAI.Probability.FreeIsing.Trees.EdgeLabelCoding
import OAI.Probability.FreeIsing.Trees.FiniteClusterSelector

namespace OAI

noncomputable section
open MeasureTheory

namespace Problem367.ClusterFactorMap

open EdgeLabelCoding

variable {d : ℕ}

abbrev Input (d : ℕ) :=
  (TreeVertex d → ℝ) × ((TreeVertex d × ℕ → ℝ) × (TreeVertex d → ℝ))

def relabelInput (g : TreeAut d) (p : Input d) : Input d :=
  (relabel g p.1, ((fun q => p.2.1 (g.toEquiv.symm q.1, q.2)), relabel g p.2.2))

def openAdj (theta : ℝ) (p : Input d) (u v : TreeVertex d) : Prop :=
  treeAdj u v ∧ edgeLabel p.1 p.2.1 u v ≤ theta

def connected (theta : ℝ) (p : Input d) : TreeVertex d → TreeVertex d → Prop :=
  Relation.ReflTransGen (openAdj theta p)

def factor (theta : ℝ) (p : Input d) : TreeVertex d → IsingSpin :=
  FiniteCluster.color (connected theta p) p.1 (fun v => fairSpin (p.2.2 v))

@[simp] lemma factor_apply (theta : ℝ) (p : Input d) (v : TreeVertex d) :
    factor theta p v =
      fairSpin (p.2.2 (FiniteCluster.selector (connected theta p) p.1 v)) := rfl

lemma openAdj_edge_iff (theta : ℝ) (p : Input d) (e : TreeEdge d) :
    openAdj theta p e.1.1 e.1.2 ↔ edgeLabels p.1 p.2.1 e ≤ theta := by
  exact and_iff_right e.2.1

lemma measurable_relabelInput (g : TreeAut d) :
    Measurable (relabelInput g) := by
  unfold relabelInput relabel
  fun_prop

lemma openAdj_sub_treeAdj (theta : ℝ) (p : Input d) {u v : TreeVertex d}
    (h : openAdj theta p u v) : treeAdj u v := h.1

lemma openAdj_symmetric (theta : ℝ) {p : Input d} (hp : Function.Injective p.1) :
    ∀ ⦃u v : TreeVertex d⦄, openAdj theta p u v → openAdj theta p v u := by
  intro u v huv
  refine ⟨adj_symm huv.1, ?_⟩
  rw [edgeLabel_swap hp p.2.1 huv.1]
  exact huv.2

lemma connected_equivalence (theta : ℝ) {p : Input d}
    (hp : Function.Injective p.1) : Equivalence (connected theta p) := by
  refine ⟨fun _ => .refl, ?_, fun h h' => h.trans h'⟩
  intro u v huv
  have hsymm := openAdj_symmetric theta hp
  apply Relation.reflTransGen_swap.mp
  exact Relation.ReflTransGen.mono (fun _ _ h => hsymm h) _ _ huv

lemma openAdj_relabel (g : TreeAut d) (theta : ℝ) (p : Input d)
    (u v : TreeVertex d) :
    openAdj theta (relabelInput g p) (g.toEquiv u) (g.toEquiv v) ↔
      openAdj theta p u v := by
  simp only [openAdj, relabelInput, g.map_adj, edgeLabel_relabel]

lemma connected_relabel (g : TreeAut d) (theta : ℝ) (p : Input d)
    (u v : TreeVertex d) :
    connected theta (relabelInput g p) (g.toEquiv u) (g.toEquiv v) ↔
      connected theta p u v := by
  exact reflTransGen_equiv_iff g.toEquiv (openAdj_relabel g theta p) u v

lemma connected_relabel_eq (g : TreeAut d) (theta : ℝ) (p : Input d) :
    connected theta (relabelInput g p) =
      fun u v => connected theta p (g.toEquiv.symm u) (g.toEquiv.symm v) := by
  funext u v
  apply propext
  simpa only [Equiv.apply_symm_apply] using
    connected_relabel g theta p (g.toEquiv.symm u) (g.toEquiv.symm v)

theorem factor_relabel (g : TreeAut d) (theta : ℝ) (p : Input d) :
    factor theta (relabelInput g p) = relabel g (factor theta p) := by
  funext v
  unfold factor
  rw [connected_relabel_eq]
  have h := FiniteCluster.color_reindex g.toEquiv (connected theta p) p.1
    (fun w => fairSpin (p.2.2 w)) (g.toEquiv.symm v)
  change FiniteCluster.color
    (fun x y => connected theta p (g.toEquiv.symm x) (g.toEquiv.symm y))
    (fun x => p.1 (g.toEquiv.symm x))
    (fun x => fairSpin (p.2.2 (g.toEquiv.symm x))) v =
      FiniteCluster.color (connected theta p) p.1
        (fun x => fairSpin (p.2.2 x)) (g.toEquiv.symm v)
  simpa only [Equiv.apply_symm_apply, Function.comp_def] using h

theorem factor_eq_of_connected (theta : ℝ) {p : Input d}
    (hp : Function.Injective p.1) {u v : TreeVertex d}
    (hu : {w | connected theta p u w}.Finite) (huv : connected theta p u v) :
    factor theta p u = factor theta p v :=
  FiniteCluster.color_eq_of_related _ (connected_equivalence theta hp) huv hu hp

theorem factor_eq_at_minimum (theta : ℝ) (p : Input d) (v a : TreeVertex d)
    (ha : FiniteCluster.IsMinimum (connected theta p) p.1 v a) :
    factor theta p v = fairSpin (p.2.2 a) := by
  unfold factor FiniteCluster.color
  rw [FiniteCluster.selector_eq_of_minimum ha]

lemma measurableSet_openAdj (theta : ℝ) (u v : TreeVertex d) :
    MeasurableSet {p : Input d | openAdj theta p u v} := by
  let : MeasurableSpace (TreeVertex d) := ⊤
  let : MeasurableSingletonClass (TreeVertex d) := ⟨fun _ => trivial⟩
  have hlabel : Measurable (fun p : Input d => edgeLabel p.1 p.2.1 u v) :=
    (measurable_edgeLabel u v).comp
      (measurable_fst.prodMk (measurable_fst.comp measurable_snd))
  exact (MeasurableSet.const (treeAdj u v)).inter
    (measurableSet_le hlabel measurable_const)

lemma measurableSet_connected (theta : ℝ) (u v : TreeVertex d) :
    MeasurableSet {p : Input d | connected theta p u v} :=
  measurableSet_reflTransGen (measurableSet_openAdj theta) u v

theorem measurable_factor (theta : ℝ) : Measurable (@factor d theta) := by
  apply FiniteCluster.measurable_color
    (connected theta) (fun p : Input d => p.1)
    (fun p : Input d => fun v => fairSpin (p.2.2 v))
  · exact measurableSet_connected theta
  · intro v
    exact (measurable_pi_apply v).comp measurable_fst
  · intro v
    exact measurable_fairSpin.comp
      ((measurable_pi_apply v).comp (measurable_snd.comp measurable_snd))

end Problem367.ClusterFactorMap

end

end OAI