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Add lean source and binary files (part 45)
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import Mathlib
import OAI.Combinatorics.IndependentSets.Repetition.Rectangle2
import OAI.Combinatorics.IndependentSets.Repetition.Overlap
namespace OAI
namespace IndependentSetsGames.Foundations.Repetition
open scoped BigOperators
open Games
noncomputable section
universe u
def TraceSeed (σ : Type u) : Nat → Type u
| 0 => PUnit
| n + 1 => σ × TraceSeed σ n
instance traceSeedFintype {σ : Type*} [Fintype σ] (n : Nat) : Fintype (TraceSeed σ n) := by
induction n with
| zero => exact inferInstanceAs (Fintype PUnit)
| succ n ih => exact inferInstanceAs (Fintype (σ × TraceSeed σ n))
instance traceSeedUniqueZero {σ : Type*} : Unique (TraceSeed σ 0) :=
inferInstanceAs (Unique PUnit)
def traceList {σ : Type*} : (n : Nat) → TraceSeed σ n → List σ
| 0, _ => []
| n + 1, seed => seed.1 :: traceList n seed.2
def traceSeedLaw {σ : Type*} [Fintype σ] (μ : FiniteDistribution σ) :
(n : Nat) → FiniteDistribution (TraceSeed σ n)
| 0 => { weight := fun _ => 1, nonnegative := by intro; norm_num,
normalized := by simp }
| n + 1 => μ.product (traceSeedLaw μ n)
theorem traceSeedLaw_expectation {σ : Type*} [Fintype σ]
(μ : FiniteDistribution σ) (n : Nat) (f : List σ → ℝ) :
(traceSeedLaw μ n).expectation (fun seed => f (traceList n seed)) =
CorrelatedSampling.traceAverage μ.weight n f := by
induction n generalizing f with
| zero => simp [traceSeedLaw, traceList, FiniteDistribution.expectation,
CorrelatedSampling.traceAverage]
| succ n ih =>
change (μ.product (traceSeedLaw μ n)).expectation
(fun seed => f (seed.1 :: traceList n seed.2)) = _
rw [FiniteDistribution.expectation_product]
simp only [CorrelatedSampling.traceAverage, FiniteDistribution.expectation]
apply Finset.sum_congr rfl
intro s _
congr 1
exact ih (fun xs => f (s :: xs))
def sharedOutputLaw {X Y S Seed : Type*}
[Fintype X] [Fintype Y] [Fintype S] [Fintype Seed] [DecidableEq S]
(μ : FiniteDistribution (X × Y)) (seedLaw : FiniteDistribution Seed)
(left : Seed → X → S) (right : Seed → Y → S) :
FiniteDistribution ((X × Y) × S × S) :=
(μ.product seedLaw).pushforward
(fun z => (z.1, left z.2 z.1.1, right z.2 z.1.2))
theorem sharedOutputLaw_weight {X Y S Seed : Type*}
[Fintype X] [Fintype Y] [Fintype S] [Fintype Seed] [DecidableEq S]
(μ : FiniteDistribution (X × Y)) (seedLaw : FiniteDistribution Seed)
(left : Seed → X → S) (right : Seed → Y → S) (x : X) (y : Y) (a b : S) :
(sharedOutputLaw μ seedLaw left right).weight ((x,y),a,b) =
μ.weight (x,y) * seedLaw.expectation
(fun seed => if left seed x = a ∧ right seed y = b then 1 else 0) := by
classical
simp only [sharedOutputLaw, FiniteDistribution.pushforward,
FiniteDistribution.product, Fintype.sum_prod_type, Prod.mk.injEq]
simp only [and_assoc, ite_and]
simp [FiniteDistribution.expectation, Finset.mul_sum, mul_ite]
open CorrelatedSampling
variable {X Y S : Type*} [Fintype X] [Fintype Y] [Fintype S]
[Nonempty S] [DecidableEq S]
def samplerLocal (thresholds : List ℝ) (profile : X → FiniteDistribution S)
(fallback : S) (n : Nat) (seed : TraceSeed (RectangleSeed thresholds S) n)
(x : X) : S :=
localSample (rectangleAccept thresholds (profile x).weight) Prod.fst fallback
(traceList n seed)
def samplerOutputLaw (thresholds : List ℝ) (μ : FiniteDistribution (X × Y))
(L : X → FiniteDistribution S) (R : Y → FiniteDistribution S)
(fallback : S) (n : Nat) : FiniteDistribution ((X × Y) × S × S) :=
sharedOutputLaw μ (traceSeedLaw (rectangleDistribution thresholds) n)
(samplerLocal thresholds L fallback n) (samplerLocal thresholds R fallback n)
omit [Nonempty S] [DecidableEq S] in
theorem probability_weight_le_one (μ : FiniteDistribution S) (s : S) : μ.weight s ≤ 1 := by
calc
μ.weight s ≤ ∑ t, μ.weight t :=
Finset.single_le_sum (fun t _ => μ.nonnegative t) (Finset.mem_univ s)
_ = 1 := μ.normalized
theorem samplerOutputLaw_diagonal (thresholds : List ℝ)
(μ : FiniteDistribution (X × Y))
(L : X → FiniteDistribution S) (R : Y → FiniteDistribution S)
(hL : ∀ x s, (L x).weight s ∈ thresholds)
(hR : ∀ y s, (R y).weight s ∈ thresholds)
(fallback : S) (n : Nat) (x : X) (y : Y) (a : S) :
μ.weight (x,y) * min ((L x).weight a) ((R y).weight a) /
(1 + Information.totalVariation (L x).weight (R y).weight) *
(1 - eventMass (rectangleWeight thresholds)
(fun s => !(rectangleAccept thresholds (L x).weight s ||
rectangleAccept thresholds (R y).weight s)) ^ n) ≤
(samplerOutputLaw thresholds μ L R fallback n).weight ((x,y),a,a) := by
have h := rectangle_label_diagonal_bound thresholds (L x).weight (R y).weight
fallback a (hL x) (hR y) (L x).nonnegative (R y).nonnegative
(probability_weight_le_one (L x)) (probability_weight_le_one (R y))
(L x).normalized (R y).normalized n
rw [samplerOutputLaw, sharedOutputLaw_weight]
have he : (traceSeedLaw (rectangleDistribution (α := S) thresholds) n).expectation
(fun seed => if samplerLocal thresholds L fallback n seed x = a ∧
samplerLocal thresholds R fallback n seed y = a then 1 else 0) =
traceAverage (rectangleWeight thresholds) n
(localDiagonal (rectangleAccept thresholds (L x).weight)
(rectangleAccept thresholds (R y).weight) Prod.fst fallback a) := by
exact traceSeedLaw_expectation (rectangleDistribution (α := S) thresholds) n
(localDiagonal (rectangleAccept thresholds (L x).weight)
(rectangleAccept thresholds (R y).weight) Prod.fst fallback a)
rw [he]
simp only [Information.totalVariation, CorrelatedSampling.totalVariation] at h ⊢
simpa only [mul_div_assoc, mul_assoc] using
mul_le_mul_of_nonneg_left h (μ.nonnegative (x,y))
theorem samplerOutputLaw_uniform_diagonal
(μ : FiniteDistribution (X × Y))
(L : X → FiniteDistribution S) (R : Y → FiniteDistribution S)
(fallback : S) (n : Nat) (x : X) (y : Y) (a : S) :
μ.weight (x,y) * min ((L x).weight a) ((R y).weight a) /
(1 + Information.totalVariation (L x).weight (R y).weight) *
(1 - uniformRejectionRate S ^ n) ≤
(samplerOutputLaw (sharedProfileThresholds L R) μ L R fallback n).weight ((x,y),a,a) := by
have hp := pow_le_pow_left₀ (sharedProfileReject_nonnegative L R x y)
(sharedProfile_reject_le_rate L R x y) n
have hco : 0 ≤ μ.weight (x,y) * min ((L x).weight a) ((R y).weight a) /
(1 + Information.totalVariation (L x).weight (R y).weight) :=
div_nonneg (mul_nonneg (μ.nonnegative (x,y))
(le_min ((L x).nonnegative a) ((R y).nonnegative a)))
(by linarith [Information.totalVariation_nonneg (L x).weight (R y).weight])
have h := samplerOutputLaw_diagonal (sharedProfileThresholds L R) μ L R
(left_mem_sharedProfileThresholds L R) (right_mem_sharedProfileThresholds L R)
fallback n x y a
exact (mul_le_mul_of_nonneg_left (sub_le_sub_left hp 1) hco).trans h
theorem samplerOutputLaw_totalVariation
(p : FiniteDistribution ((X × Y) × S)) (μ : FiniteDistribution (X × Y))
(L : X → FiniteDistribution S) (R : Y → FiniteDistribution S)
(fallback : S) (n : Nat) :
Information.totalVariation
(samplerOutputLaw (sharedProfileThresholds L R) μ L R fallback n).weight
(diagonalWeights p.weight) ≤
2 * Information.totalVariation p.weight (fun z => μ.weight z.1 * (L z.1.1).weight z.2) +
2 * Information.totalVariation p.weight (fun z => μ.weight z.1 * (R z.1.2).weight z.2) +
uniformRejectionRate S ^ n := by
apply diagonal_sampler_totalVariation_le p.weight μ.weight
(fun xy => (L xy.1).weight) (fun xy => (R xy.2).weight) _
(Information.gameLaw_isProbability p) (Information.gameLaw_isProbability μ)
(fun xy => Information.gameLaw_isProbability (L xy.1))
(fun xy => Information.gameLaw_isProbability (R xy.2))
(Information.gameLaw_isProbability _)
(pow_nonneg (uniformRejectionRate_nonnegative S) n)
· exact pow_le_one₀ (uniformRejectionRate_nonnegative S)
(uniformRejectionRate_lt_one S).le
· intro xy a
exact samplerOutputLaw_uniform_diagonal μ L R fallback n xy.1 xy.2 a
theorem samplerOutputLaw_arbitrarily_close
(p : FiniteDistribution ((X × Y) × S)) (μ : FiniteDistribution (X × Y))
(L : X → FiniteDistribution S) (R : Y → FiniteDistribution S)
(fallback : S) (η : ℝ) (hη : 0 < η) : ∃ n : Nat,
Information.totalVariation
(samplerOutputLaw (sharedProfileThresholds L R) μ L R fallback n).weight
(diagonalWeights p.weight) ≤
2 * Information.totalVariation p.weight (fun z => μ.weight z.1 * (L z.1.1).weight z.2) +
2 * Information.totalVariation p.weight (fun z => μ.weight z.1 * (R z.1.2).weight z.2) + η := by
obtain ⟨n,hn⟩ := exists_uniformRejectionRate_pow_lt S η hη
exact ⟨n, (samplerOutputLaw_totalVariation p μ L R fallback n).trans
(by linarith)⟩
end
end IndependentSetsGames.Foundations.Repetition
end OAI