File size: 5,813 Bytes
dd14c26
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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
import OAI.Probability.MatroidProphet.Main

namespace OAI

/-! The manuscript writes the observed rank mask as `D ∪ C`, whereas the
algorithm also removes `H`.  The two definitions coincide on every candidate
group, including empty and unlisted groups.  These lemmas discharge that
semantic identification without adding a premise to a source theorem. -/

namespace MatroidProphet.SourceRankMask
open Set Finset MainAlgorithm
variable {α : Type*} [Fintype α]

omit [Fintype α] in
lemma sdiff_union_of_subset_disjoint (S U H O : Set α)
    (hSU : S ⊆ U) (hUH : Disjoint U H) : S \ (H ∪ O) = S \ O := by
  ext e
  constructor
  · rintro ⟨he, hn⟩
    exact ⟨he, fun ho => hn (Or.inr ho)⟩
  · rintro ⟨he, hn⟩
    refine ⟨he, ?_⟩
    rintro (hh | ho)
    · exact Set.disjoint_left.mp hUH (hSU he) hh
    · exact hn ho

lemma nominalLayerSet_sdiff_union (M : Matroid α) (hE : M.E = Set.univ)
    (κ : ℕ) (D C : ℕ → Set α) (h : ℕ) (U H O : Set α) (ε : Fin 2)
    (b : Pivots.ParityWindow (activation h) ε) (hUH : Disjoint U H) :
    nominalLayerSet M hE κ D C h U ε b \ (H ∪ O) =
      nominalLayerSet M hE κ D C h U ε b \ O :=
  sdiff_union_of_subset_disjoint _ U H O
    (nominalLayerSet_subset M hE κ D C h U ε b) hUH

lemma nominalRankStatistic_mask_union (M : Matroid α) (hE : M.E = Set.univ)
    (κ : ℕ) (D C T : ℕ → Set α) (h : ℕ) (U H O : Set α) (ε : Fin 2)
    (hUH : Disjoint U H) :
    nominalRankStatistic M hE κ D C T h U (H ∪ O) ε =
      nominalRankStatistic M hE κ D C T h U O ε := by
  unfold nominalRankStatistic
  apply Finset.sum_congr rfl
  intro b _
  rw [nominalLayerSet_sdiff_union M hE κ D C h U H O ε b hUH]

lemma testRankStatistic_mask_union (M : Matroid α) (hE : M.E = Set.univ)
    (κ : ℕ) (D C T : ℕ → Set α) (h : ℕ) (U H O test : Set α) (ε : Fin 2)
    (hUH : Disjoint U H) :
    testRankStatistic M hE κ D C T h U (H ∪ O) test ε =
      testRankStatistic M hE κ D C T h U O test ε := by
  unfold testRankStatistic
  apply Finset.sum_congr rfl
  intro b _
  rw [nominalLayerSet_sdiff_union M hE κ D C h U H O ε b hUH]

lemma finalRankStatistic_mask_union (M : Matroid α) (hE : M.E = Set.univ)
    (κ : ℕ) (D C T : ℕ → Set α) (h final : ℕ) (U H O test : Set α) (ε : Fin 2)
    (hUH : Disjoint U H) :
    finalRankStatistic M hE κ D C T h final U (H ∪ O) test ε =
      finalRankStatistic M hE κ D C T h final U O test ε := by
  unfold finalRankStatistic
  apply Finset.sum_congr rfl
  intro b _
  rw [nominalLayerSet_sdiff_union M hE κ D C h U H O ε b hUH]

variable {n : ℕ}

lemma groupMask_disjoint_H (M : Matroid (Fin n)) (d : MainMasks n)
    (w : Fin n → Option ℤ) (mask : Finset (Fin n)) (h : ℕ) :
    Disjoint (groupMask M d w mask h) (d.H : Set (Fin n)) := by
  apply Set.disjoint_left.mpr
  intro e he hh
  exact he.2.1.2.1 hh

/-- Exact source mask for the nominal statistic; no listing hypothesis. -/
lemma listedZ_sourceMask (M : Matroid (Fin n)) (hE : M.E = Set.univ)
    (d : MainMasks n) (w : Fin n → Option ℤ) (h : ℕ) :
    listedZ M hE d w h =
      nominalRankStatistic M hE (2^100) (groupMask M d w d.D) (groupMask M d w d.C)
        (groupMask M d w d.T) h (groupMask M d w univ h)
        ((d.D ∪ d.C : Finset (Fin n)) : Set (Fin n)) (boolParity d.odd) := by
  unfold listedZ
  simpa only [Finset.coe_union, Set.union_assoc] using
    nominalRankStatistic_mask_union M hE (2^100) (groupMask M d w d.D)
      (groupMask M d w d.C) (groupMask M d w d.T) h (groupMask M d w univ h)
      (d.H : Set (Fin n)) ((d.D ∪ d.C : Finset (Fin n)) : Set (Fin n))
      (boolParity d.odd) (groupMask_disjoint_H M d w univ h)

/-- Exact source mask for the final statistic used in the all-orders bound. -/
lemma listedLambda_sourceMask (M : Matroid (Fin n)) (hE : M.E = Set.univ)
    (d : MainMasks n) (w : Fin n → Option ℤ) (h : ℕ) :
    listedLambda M hE d w h =
      finalRankStatistic M hE (2^100) (groupMask M d w d.D) (groupMask M d w d.C)
        (groupMask M d w d.T) h (groups M d w).length (groupMask M d w univ h)
        ((d.D ∪ d.C : Finset (Fin n)) : Set (Fin n)) (d.T : Set (Fin n))
        (boolParity d.odd) := by
  unfold listedLambda
  simpa only [Finset.coe_union, Set.union_assoc] using
    finalRankStatistic_mask_union M hE (2^100) (groupMask M d w d.D)
      (groupMask M d w d.C) (groupMask M d w d.T) h (groups M d w).length
      (groupMask M d w univ h) (d.H : Set (Fin n))
      ((d.D ∪ d.C : Finset (Fin n)) : Set (Fin n)) (d.T : Set (Fin n))
      (boolParity d.odd) (groupMask_disjoint_H M d w univ h)

/-- Exact nominal statistic in the transfer section, including its zero branch. -/
lemma listedRankStatistic_sourceMask (M : Matroid (Fin n)) (hE : M.E = Set.univ)
    (κ : ℕ) (d : MainMasks n) (w : Fin n → Option ℤ) (i : ℤ) (ε : Fin 2) :
    listedRankStatistic M hE κ d w i ε =
      if i ∈ groups M d w then
        nominalRankStatistic M hE κ (groupMask M d w d.D) (groupMask M d w d.C)
          (groupMask M d w d.T) ((groups M d w).idxOf i)
          (trueGroup M d w i : Set (Fin n))
          ((d.D ∪ d.C : Finset (Fin n)) : Set (Fin n)) ε
      else 0 := by
  classical
  have hUH : Disjoint (trueGroup M d w i : Set (Fin n)) (d.H : Set (Fin n)) := by
    apply Set.disjoint_left.mpr
    intro e he hh
    exact ((mem_trueGroup M d w i e).mp he).1.2.1 hh
  unfold listedRankStatistic
  split_ifs
  · simpa only [Finset.coe_union, Set.union_assoc] using
      nominalRankStatistic_mask_union M hE κ (groupMask M d w d.D)
        (groupMask M d w d.C) (groupMask M d w d.T) ((groups M d w).idxOf i)
        (trueGroup M d w i : Set (Fin n)) (d.H : Set (Fin n))
        ((d.D ∪ d.C : Finset (Fin n)) : Set (Fin n)) ε hUH
  · rfl

end MatroidProphet.SourceRankMask

end OAI