File size: 6,409 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
import OAI.Probability.MatroidProphet.Residual.Gap
import OAI.Probability.MatroidProphet.GroupConditioning
import OAI.Probability.MatroidProphet.SafeParity

namespace OAI

namespace MatroidProphet.MainAlgorithm
open Finset Pivots
variable {n : ℕ}

noncomputable def listedTransferGap (M : Matroid (Fin n)) (hE : M.E = Set.univ)
    (κ : ℕ) (d : MainMasks n) (s : Fin n → Option ℤ) (i : ℤ)
    (Y : Set (Fin n)) (ε : Fin 2) : ℝ :=
  max ((listedSafeStatistic M hE κ d s i Y ε : ℝ) -
    (κ : ℝ) * listedRankStatistic M hE κ d s i ε) 0

lemma trueGroup_nonloop (M : Matroid (Fin n)) (d : MainMasks n)
    (s : Fin n → Option ℤ) (i : ℤ) :
    ∀ e ∈ trueGroup M d s i, e ∉ M.closure ∅ := by
  intro e he hl
  have hc := (mem_trueGroup M d s i e).mp he
  exact hc.1.2.2 (M.closure_mono (Set.empty_subset _) hl)

noncomputable def focalResidualFamily (M : Matroid (Fin n)) (hE : M.E = Set.univ)
    (κ : ℕ) (d : MainMasks n) (s : Fin n → Option ℤ) (i : ℤ) (ε : Fin 2) :
    Finset (Finset (Fin n)) :=
  let r := focalReference M d s i
  labeledResidualFamily M (trueGroup M d s i) κ
    (guardedPath M hE κ (groupMask M r s r.D) (groupMask M r s r.C) (focalIndex M d s i))
    (activation (focalIndex M d s i)) ε
    (fun b => lowerCompetition M hE κ (groupMask M r s r.D) (groupMask M r s r.C)
      (groupMask M r s r.T) b.val.val (focalIndex M d s i))

lemma listedTransferGap_focal_le (M : Matroid (Fin n)) (hE : M.E = Set.univ)
    (κ : ℕ) (hκ : 0 < κ) (d : MainMasks n) (s : Fin n → Option ℤ) (i : ℤ)
    (Y : Set (Fin n)) (hY : Y ⊆ (trueGroup M d s i : Set (Fin n)))
    (ε : Fin 2) (A B C : Finset (Fin n))
    (hA : A ⊆ trueGroup M d s i) (hB : B ⊆ trueGroup M d s i)
    (hC : C ⊆ trueGroup M d s i) :
    listedTransferGap M hE κ (focalMasks d (trueGroup M d s i) A B C) s i Y ε ≤
      residualDelta * (trueGroup M d s i).card + ((trueGroup M d s i).card : ℝ) *
        residualBadIndicator (focalResidualFamily M hE κ d s i ε)
          (residualDelta * (trueGroup M d s i).card) (A ∪ B) := by
  classical
  by_cases hne : A.Nonempty
  · let f := focalMasks d (trueGroup M d s i) A B C
    have hg : groupMask M f s f.D (focalIndex M d s i) = (A : Set (Fin n)) :=
      focal_group_mask M d s i A B C d.D A hA hne hA
    have hDU : groupMask M f s f.D (focalIndex M d s i) ⊆ (trueGroup M d s i : Set (Fin n)) := by
      rw [hg]
      exact hA
    have hI : (f.D : Set (Fin n)) ∩ Y ⊆ groupMask M f s f.D (focalIndex M d s i) := by
      rw [hg, focal_density_inter M d s i A B C Y hY]
      exact Set.inter_subset_left
    have hOS : ((f.H ∪ f.D ∪ f.C : Finset (Fin n)) : Set (Fin n)) ∩
        (trueGroup M d s i : Set (Fin n)) ⊆ ((A ∪ B : Finset (Fin n)) : Set (Fin n)) := by
      have he := congrArg (fun X : Finset (Fin n) => (X : Set (Fin n)))
        (focal_observed_inter M d s i A B C hA hB)
      simpa only [coe_inter] using he.subset
    have h := nominalTransferGap_le_bad M hE κ hκ (groupMask M f s f.D)
      (groupMask M f s f.C) (groupMask M f s f.T) (focalIndex M d s i)
      (trueGroup M d s i) (A ∪ B) ((f.H ∪ f.D ∪ f.C : Finset (Fin n)) : Set (Fin n))
      ((f.D : Set (Fin n)) ∩ Y) hDU hI (union_subset hA hB) hOS
      (trueGroup_nonloop M d s i) ε
    have hF := funext (focal_incoming_path M hE κ d s i A B C hA hB hC hne)
    have hK := funext (fun b : ParityWindow (activation (focalIndex M d s i)) ε =>
      focal_lowerCompetition M hE κ d s i A B C hA hB hC hne b.val.val)
    rw [hF, hK] at h
    simpa only [listedTransferGap, listedSafeStatistic_focal_nonempty M hE κ d s i A B C Y ε hA hne,
      listedRankStatistic_focal_nonempty M hE κ d s i A B C ε hA hne,
      nominalTransferGap, focalResidualFamily] using h
  · have hAe : A = ∅ := not_nonempty_iff_eq_empty.mp hne
    subst A
    rw [listedTransferGap, listedSafeStatistic_focal_empty, listedRankStatistic_focal_empty]
    simp only [Nat.cast_zero, mul_zero, sub_zero, max_self]
    apply add_nonneg (mul_nonneg residualDelta_nonneg (Nat.cast_nonneg _))
    apply mul_nonneg (Nat.cast_nonneg _)
    unfold residualBadIndicator
    split_ifs <;> norm_num

lemma focalTransferGap_expectation_le (M : Matroid (Fin n)) (hE : M.E = Set.univ)
    (d : MainMasks n) (s : Fin n → Option ℤ) (i : ℤ) (Y : Set (Fin n))
    (hY : Y ⊆ (trueGroup M d s i : Set (Fin n)))
    (hn : densityThreshold ≤ ((trueGroup M d s i).card : ℝ)) (ε : Fin 2) :
    tripleMaskExpectation (fun _ => (1:ℝ)/4) (fun _ => thinningRate) (fun _ => thinningRate)
      (trueGroup M d s i) (fun A B C =>
        listedTransferGap M hE (2^100) (focalMasks d (trueGroup M d s i) A B C) s i Y ε) ≤
      2 * residualDelta * (trueGroup M d s i).card := by
  have ht0 : 0 ≤ thinningRate := constants_positive.2.2.1.le
  have ht1 : thinningRate ≤ 1 := by norm_num [thinningRate]
  have hu : (1:ℝ)/4 + (1-(1:ℝ)/4)*thinningRate ≤ 1/2 := by norm_num [thinningRate]
  have hne : (trueGroup M d s i).Nonempty := by
    apply card_pos.mp
    have hp := lt_of_lt_of_le constants_positive.2.1 hn
    exact_mod_cast hp
  apply tripleMask_residual_error_le (fun _ => (1:ℝ)/4) (fun _ => thinningRate)
    (fun _ => thinningRate) (fun _ => by norm_num) (fun _ => by norm_num)
    (fun _ => ht0) (fun _ => ht1) (fun _ => ht0) (fun _ => ht1) (fun _ => hu)
    (trueGroup M d s i) (focalResidualFamily M hE (2^100) d s i ε)
  · exact labeledResidualFamily_subsets M _ _ _ _ ε _
  · have hc := labeledResidualFamily_card M hE (trueGroup M d s i) hne (2^100)
        (by norm_num) (guardedPath M hE (2^100)
          (groupMask M (focalReference M d s i) s (focalReference M d s i).D)
          (groupMask M (focalReference M d s i) s (focalReference M d s i).C) (focalIndex M d s i))
        (activation (focalIndex M d s i)) ε
        (fun b => lowerCompetition M hE (2^100)
          (groupMask M (focalReference M d s i) s (focalReference M d s i).D)
          (groupMask M (focalReference M d s i) s (focalReference M d s i).C)
          (groupMask M (focalReference M d s i) s (focalReference M d s i).T) b.val.val (focalIndex M d s i))
    simpa only [Nat.cast_pow, Nat.cast_ofNat, densityThreshold, focalResidualFamily] using hc
  · exact hn
  · intro A hA B hB C hC
    exact listedTransferGap_focal_le M hE (2^100) (by positivity) d s i Y hY ε A B C hA hB hC

end MatroidProphet.MainAlgorithm

end OAI