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Add lean source and binary files (part 64)
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import Mathlib
import OAI.Computability.VertexCover.Games.Basic
namespace OAI
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namespace UniqueGames.Foundations.Games
open scoped BigOperators
noncomputable section
namespace Game
variable {Q₁ Q₂ A₁ A₂ : Type*}
[Fintype Q₁] [Fintype Q₂] [Fintype A₁] [Fintype A₂]
[Nonempty A₁] [Nonempty A₂]
def value (G : Game Q₁ Q₂ A₁ A₂) : ℝ := by
classical
exact Finset.univ.sup' Finset.univ_nonempty G.success
theorem success_le_value (G : Game Q₁ Q₂ A₁ A₂)
(strategy : Strategy Q₁ Q₂ A₁ A₂) : G.success strategy ≤ G.value := by
classical
exact Finset.le_sup' G.success (Finset.mem_univ strategy)
theorem value_le_iff (G : Game Q₁ Q₂ A₁ A₂) (bound : ℝ) :
G.value ≤ bound ↔ ∀ strategy : Strategy Q₁ Q₂ A₁ A₂, G.success strategy ≤ bound := by
classical
simp [value, Finset.sup'_le_iff]
theorem exists_optimal_strategy (G : Game Q₁ Q₂ A₁ A₂) :
∃ strategy : Strategy Q₁ Q₂ A₁ A₂, G.success strategy = G.value := by
classical
obtain ⟨strategy, _, h⟩ := Finset.exists_mem_eq_sup'
(s := (Finset.univ : Finset (Strategy Q₁ Q₂ A₁ A₂))) Finset.univ_nonempty G.success
exact ⟨strategy, h.symm⟩
theorem value_nonnegative (G : Game Q₁ Q₂ A₁ A₂) : 0 ≤ G.value := by
obtain ⟨strategy, h⟩ := G.exists_optimal_strategy
rw [← h]
exact G.success_nonnegative strategy
theorem value_le_one (G : Game Q₁ Q₂ A₁ A₂) : G.value ≤ 1 :=
(G.value_le_iff 1).2 G.success_le_one
theorem randomized_success_le_value (G : Game Q₁ Q₂ A₁ A₂)
{Seed : Type*} [Fintype Seed] (seedLaw : FiniteDistribution Seed)
(strategies : Seed → Strategy Q₁ Q₂ A₁ A₂) :
seedLaw.expectation (fun seed => G.success (strategies seed)) ≤ G.value := by
unfold FiniteDistribution.expectation
calc
_ ≤ ∑ seed, seedLaw.weight seed * G.value := by
apply Finset.sum_le_sum
intro seed _
exact mul_le_mul_of_nonneg_left (G.success_le_value _) (seedLaw.nonnegative seed)
_ = G.value := by rw [← Finset.sum_mul, seedLaw.normalized, one_mul]
omit [Nonempty A₁] [Nonempty A₂] in
theorem success_repetition_zero (G : Game Q₁ Q₂ A₁ A₂)
(strategy : Strategy (Fin 0 → Q₁) (Fin 0 → Q₂) (Fin 0 → A₁) (Fin 0 → A₂)) :
(G.repetition 0).success strategy = 1 := by
have h : (G.repetition 0).wins strategy = fun _ => true := by
funext questions
simp [wins, repetition]
unfold success
rw [h, FiniteDistribution.probability_true]
@[simp] theorem value_repetition_zero (G : Game Q₁ Q₂ A₁ A₂) :
(G.repetition 0).value = 1 := by
obtain ⟨strategy, h⟩ := (G.repetition 0).exists_optimal_strategy
rw [← h]
exact G.success_repetition_zero strategy
theorem pow_value_le_repetition_value (G : Game Q₁ Q₂ A₁ A₂) (n : Nat) :
G.value ^ n ≤ (G.repetition n).value := by
obtain ⟨strategy, h⟩ := G.exists_optimal_strategy
rw [← h, ← G.success_repeatStrategy strategy n]
exact (G.repetition n).success_le_value (repeatStrategy strategy n)
theorem value_le_of_localSimulation {R₁ R₂ B₁ B₂ : Type*}
[Fintype R₁] [Fintype R₂] [Fintype B₁] [Fintype B₂]
[Nonempty B₁] [Nonempty B₂]
(G : Game Q₁ Q₂ A₁ A₂) (H : Game R₁ R₂ B₁ B₂)
(questionMap₁ : Q₁ → R₁) (questionMap₂ : Q₂ → R₂)
(answerMap₁ : Q₁ → B₁ → A₁) (answerMap₂ : Q₂ → B₂ → A₂)
(questionLaw : H.questions =
G.questions.pushforward (fun q => (questionMap₁ q.1, questionMap₂ q.2)))
(acceptance : ∀ x y a b,
H.accepts (questionMap₁ x) (questionMap₂ y) a b = true →
G.accepts x y (answerMap₁ x a) (answerMap₂ y b) = true) :
H.value ≤ G.value := by
apply (H.value_le_iff _).2
intro strategy
exact (G.success_le_of_localSimulation H questionMap₁ questionMap₂
answerMap₁ answerMap₂ questionLaw acceptance strategy).trans (G.success_le_value _)
end Game
end
end UniqueGames.Foundations.Games
end
end
end
end
end
end
end
end
end
end
end
end
end
end
end
end
end
end
end
end
end
end
end
end
end OAI