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MIPRE.Background.Repetition.CommutingRepetition.Game.Monotone

theorem CommutingRepetition.Game.repeat_omegaCO_le {X Y A B : Type} [Fintype X] [Fintype Y] [Fintype A] [Fintype B] [Nonempty X] [Nonempty Y] [Nonempty A] [Nonempty B] (G : Game X Y A B) (n : ) (hn : 1 n) :

Marginal monotonicity (node 1.6.1; 07_main_theorem.tex, eq marginal-monotonicity): ω^co(G^{⊗n}) ≤ ω^co(G) for every n ≥ 1. Stated for arbitrary [0,1] payoffs — a disclosed safe-direction strengthening of the manuscript's predicate-context display (DIFFERENCES.md D11). Proof: presample the other n − 1 question pairs with shared randomness (the seed mixture of Game/Mixture.lean), play the chosen coordinate i, and marginalize the answers; the product payoff is bounded by the coordinate-i payoff since all factors lie in [0,1].

theorem CommutingRepetition.Game.abs_win_sub_win_le {X Y A B : Type} [Fintype X] [Fintype Y] [Fintype A] [Fintype B] {G₁ G₂ : Game X Y A B} {δ : } ( : 0 δ) ( : G₁.questionWeight = G₂.questionWeight) (hV : ∀ (x : X) (y : Y) (a : A) (b : B), |G₁.payoff x y a b - G₂.payoff x y a b| δ) {p : Correlation X Y A B} (hp : ∀ (x : X) (y : Y) (a : A) (b : B), 0 p x y a b) (hsum : ∀ (x : X) (y : Y), a : A, b : B, p x y a b 1) :
|G₁.win p - G₂.win p| δ

Payoff perturbation for the winning functional (node 1.6.3; 07_main_theorem.tex, eq payoff-rational-approximation, first inequality): two games with the same question law and δ-close payoff tables give winning probabilities within δ, for any subnormalized nonnegative correlation. ( is needed for degenerate empty alphabets, where the payoff hypothesis is vacuous and both wins are zero.)

theorem CommutingRepetition.Game.abs_omegaCO_sub_omegaCO_le {X Y A B : Type} [Fintype X] [Fintype Y] [Fintype A] [Fintype B] [Nonempty A] [Nonempty B] {G₁ G₂ : Game X Y A B} {δ : } ( : 0 δ) ( : G₁.questionWeight = G₂.questionWeight) (hV : ∀ (x : X) (y : Y) (a : A) (b : B), |G₁.payoff x y a b - G₂.payoff x y a b| δ) :
|G₁.omegaCO - G₂.omegaCO| δ

Payoff perturbation for the commuting value (node 1.6.3): δ-close payoff tables give δ-close values. ["The same bounds hold after taking commuting suprema", 07_main_theorem.tex]

theorem CommutingRepetition.Game.abs_repeat_omegaCO_sub_le {X Y A B : Type} [Fintype X] [Fintype Y] [Fintype A] [Fintype B] [Nonempty A] [Nonempty B] {G₁ G₂ : Game X Y A B} {δ : } ( : 0 δ) ( : G₁.questionWeight = G₂.questionWeight) (hV : ∀ (x : X) (y : Y) (a : A) (b : B), |G₁.payoff x y a b - G₂.payoff x y a b| δ) (n : ) :
|(G₁.repeat n).omegaCO - (G₂.repeat n).omegaCO| n * δ

Repeated-game payoff perturbation (node 1.6.3; 07_main_theorem.tex, eq payoff-rational-approximation, second inequality, "telescoping the product"): δ-close payoff tables give n·δ-close repeated values.