File size: 7,901 Bytes
cdec422
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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
import Mathlib
import OAI.LinearAlgebra.MatrixFields.Extraction.ConditionalLabels

namespace OAI

namespace MatrixAllFields

open scoped BigOperators Topology Polynomial

noncomputable section

namespace MatrixMultiplication.ConditionalLabels

open MatrixMultiplication.Foundation Filter StageHierarchyResources HierarchySeparationRates
open LabelHierarchyCounts
open scoped BigOperators Topology Classical

universe u v
variable {A : Type u} [Fintype A] {Label : ℕ → Type v}
  [∀ n, Fintype (Label n)]

def normalizedCountLaw (counts : A → ℕ) (hD : 0 < ∑ a, counts a) : FiniteLaw A where
  mass a := (counts a : ℝ) / (∑ b, counts b : ℕ)
  nonneg a := div_nonneg (Nat.cast_nonneg _) (Nat.cast_nonneg _)
  total := by
    rw [← Finset.sum_div, ← Nat.cast_sum]
    exact div_self (Nat.cast_ne_zero.mpr (Nat.ne_of_gt hD))

@[simp] theorem normalizedCountLaw_mass (counts : A → ℕ)
    (hD : 0 < ∑ a, counts a) (a : A) :
    (normalizedCountLaw counts hD).mass a =
      (counts a : ℝ) / (∑ b, counts b : ℕ) := rfl

theorem normalized_prefix_mass (counts : A → ℕ) (p : FiniteLaw A)
    (mass : ∀ a, p.mass a = (counts a : ℝ) / (∑ b, counts b : ℕ))
    (labels : ∀ n, A → Label n) (n : ℕ) (r : LabelRecord Label n) :
    (p.map (labelRecordOf labels n)).mass r =
      (sourcePrefixCounts counts labels n r : ℝ) / (∑ a, counts a : ℕ) := by
  simp only [FiniteLaw.map_mass, mass, sourcePrefixCounts, pushforwardCounts,
    Nat.cast_sum, Finset.sum_div]
  apply Finset.sum_congr rfl
  intro a _
  by_cases h : labelRecordOf labels n a = r <;> simp [h]

theorem zero_prefix_contribution_of_count_eq_zero (counts : A → ℕ) (p : FiniteLaw A)
    (mass : ∀ a, p.mass a = (counts a : ℝ) / (∑ b, counts b : ℕ))
    (labels : ∀ n, A → Label n) (n : ℕ) (r : LabelRecord Label n)
    (hzero : sourcePrefixCounts counts labels n r = 0) :
    (p.map (labelRecordOf labels n)).mass r *
      finiteEntropy ((p.conditional (labelRecordOf labels n) r).map (labels n)).mass = 0 := by
  rw [normalized_prefix_mass counts p mass labels n r, hzero,
    Nat.cast_zero, zero_div, zero_mul]

theorem tendsto_log_prefix_multinomial (counts : A → ℕ)
    (hD : 0 < ∑ a, counts a) (p : FiniteLaw A)
    (mass : ∀ a, p.mass a = (counts a : ℝ) / (∑ b, counts b : ℕ))
    (labels : ∀ n, A → Label n) (n : ℕ) :
    Tendsto (fun t : ℕ => Real.log
      (Nat.multinomial Finset.univ
        (sourcePrefixCounts (fun a => t * counts a) labels n) : ℝ) /
        ((t : ℝ) * (∑ a, counts a : ℕ))) atTop
      (𝓝 (finiteEntropy (p.map (labelRecordOf labels n)).mass)) := by
  have hsum : (∑ r, sourcePrefixCounts counts labels n r) = ∑ a, counts a :=
    pushforwardCounts_sum counts (labelRecordOf labels n)
  have hpositive : 0 < ∑ r, sourcePrefixCounts counts labels n r := by rwa [hsum]
  have hmass : (fun r => (sourcePrefixCounts counts labels n r : ℝ) /
      (∑ r, sourcePrefixCounts counts labels n r : ℕ)) =
      (p.map (labelRecordOf labels n)).mass := by
    funext r
    rw [hsum]
    exact (normalized_prefix_mass counts p mass labels n r).symm
  have h := tendsto_log_multinomial_mul (sourcePrefixCounts counts labels n) hpositive
  rw [hmass, hsum] at h
  have hscale (t : ℕ) : sourcePrefixCounts (fun a => t * counts a) labels n =
      (fun r => t * sourcePrefixCounts counts labels n r) :=
    funext (sourcePrefixCounts_mul counts labels t n)
  simpa only [hscale] using h

theorem stageEntropyRate_div_eq_refinementEntropy (counts : A → ℕ)
    (hD : 0 < ∑ a, counts a) (p : FiniteLaw A)
    (mass : ∀ a, p.mass a = (counts a : ℝ) / (∑ b, counts b : ℕ))
    (labels : ∀ n, A → Label n) (depth n : ℕ) (hn : n < depth) :
    stageEntropyRate counts labels n / (∑ a, counts a : ℕ) =
      (FiniteLabelHierarchy.ofLawLabels p labels depth).refinementEntropy n := by
  have hstage := (tendsto_log_stageRefinementCount_div counts labels n).div_const
    ((∑ a, counts a : ℕ) : ℝ)
  simp only [div_div] at hstage
  have hcoarse := tendsto_log_prefix_multinomial counts hD p mass labels n
  have hfine := tendsto_log_prefix_multinomial counts hD p mass labels (n + 1)
  have heq : finiteEntropy (p.map (labelRecordOf labels (n + 1))).mass =
      finiteEntropy (p.map (labelRecordOf labels n)).mass +
        stageEntropyRate counts labels n / (∑ a, counts a : ℕ) := by
    apply tendsto_nhds_unique hfine
    apply (hcoarse.add hstage).congr
    intro t
    rw [multinomial_succ (sourcePrefixCounts (fun a => t * counts a) labels) n
      (sourcePrefixCounts_compatible (fun a => t * counts a) labels n)]
    have hcoarse_pos : 0 < Nat.multinomial Finset.univ
        (sourcePrefixCounts (fun a => t * counts a) labels n) := Nat.multinomial_pos _ _
    have hrefinement_pos : 0 <
        refinementCount (sourcePrefixCounts (fun a => t * counts a) labels) n :=
      stageRefinementCount_pos counts labels n t
    rw [Nat.cast_mul, Real.log_mul
      (Nat.cast_ne_zero.mpr (Nat.ne_of_gt hcoarse_pos))
      (Nat.cast_ne_zero.mpr (Nat.ne_of_gt hrefinement_pos)), add_div]
    rfl
  have hchain := (FiniteLabelHierarchy.ofLawLabels p labels depth).prefixLaw_entropy_succ
    n (Nat.succ_le_of_lt hn)
  rw [FiniteLabelHierarchy.ofLawLabels_prefixLaw_mass,
    FiniteLabelHierarchy.ofLawLabels_prefixLaw_mass] at hchain
  linarith

theorem stagePairingRate_div_eq_lawPairingRate (counts : A → ℕ)
    (hD : 0 < ∑ a, counts a) (p : FiniteLaw A)
    (mass : ∀ a, p.mass a = (counts a : ℝ) / (∑ b, counts b : ℕ))
    (labels : ∀ n, A → Label n) (depth : ℕ)
    (reader : Fin depth → ReaderPair) (pair : ReaderPair) :
    stagePairingRate counts labels depth reader pair / (∑ a, counts a : ℕ) =
      lawPairingRate p labels depth reader pair := by
  unfold stagePairingRate lawPairingRate pairingRate
  rw [Finset.sum_div]
  apply Finset.sum_congr rfl
  intro n _
  by_cases h : reader n = pair
  · simp only [h, ite_true]
    exact stageEntropyRate_div_eq_refinementEntropy counts hD p mass labels depth n.val n.isLt
  · simp [h]

theorem tendsto_log_stagePairingSize_law (counts : A → ℕ)
    (hD : 0 < ∑ a, counts a) (p : FiniteLaw A)
    (mass : ∀ a, p.mass a = (counts a : ℝ) / (∑ b, counts b : ℕ))
    (labels : ∀ n, A → Label n) (depth : ℕ)
    (reader : Fin depth → ReaderPair) (pair : ReaderPair) :
    Tendsto (fun t => Real.log (stagePairingSize counts labels depth reader pair t : ℝ) /
      ((t : ℝ) * (∑ a, counts a : ℕ))) atTop
      (𝓝 (lawPairingRate p labels depth reader pair)) := by
  rw [← stagePairingRate_div_eq_lawPairingRate counts hD p mass labels depth reader pair]
  exact tendsto_log_stagePairingSize_normalized counts labels depth reader pair

theorem stageEntropyRate_div_eq_normalizedCountLaw_refinementEntropy
    (counts : A → ℕ) (hD : 0 < ∑ a, counts a)
    (labels : ∀ n, A → Label n) (depth n : ℕ) (hn : n < depth) :
    stageEntropyRate counts labels n / (∑ a, counts a : ℕ) =
      (FiniteLabelHierarchy.ofLawLabels (normalizedCountLaw counts hD)
        labels depth).refinementEntropy n :=
  stageEntropyRate_div_eq_refinementEntropy counts hD (normalizedCountLaw counts hD)
    (fun _ => rfl) labels depth n hn

theorem tendsto_log_stagePairingSize_normalizedCountLaw
    (counts : A → ℕ) (hD : 0 < ∑ a, counts a)
    (labels : ∀ n, A → Label n) (depth : ℕ)
    (reader : Fin depth → ReaderPair) (pair : ReaderPair) :
    Tendsto (fun t => Real.log (stagePairingSize counts labels depth reader pair t : ℝ) /
      ((t : ℝ) * (∑ a, counts a : ℕ))) atTop
      (𝓝 (lawPairingRate (normalizedCountLaw counts hD) labels depth reader pair)) :=
  tendsto_log_stagePairingSize_law counts hD (normalizedCountLaw counts hD)
    (fun _ => rfl) labels depth reader pair

end MatrixMultiplication.ConditionalLabels

end

end MatrixAllFields

end OAI