AFTD Auto-Formalizing Theoretical Domains

StrategicGame

structure

A strategic-form game with player type Player consists of a family of strategy types Strategy i for each player i : Player, and a real-valued payoff function payoff i : (∀ j : Player, Strategy j) → ℝ for each player i : Player.

Statement

structure StrategicGame (Player : Type*)
Source
Osborne & Rubinstein, A Course in Game Theory, Def 11.1; Fudenberg & Tirole, Game Theory, Def 1.1
Verified
07 Sep 2026
Axioms
none listed
Used by 3
  • is_pure_nash_equilibriumIn a strategic-form game G with player type Player, a strategy profile s : ∀ i, G.Strategy i is a pure Nash equilibrium if for every…
  • not_pure_nash_of_exists_better_responseIn a strategic-form game G, if some player i has an alternative strategy s_i' yielding a strictly higher payoff than at strategy profile s…
  • pure_nash_of_common_payoff_maximizerIn a strategic-form game G where all players have the same payoff function u (that is, G.payoff i s = u s for every player i and strategy…

Read back from the Lean

A structure StrategicGame parameterized by a type Player : Type*, consisting of: 1. Strategy: a function assigning to each player i : Player a type Strategy i of available strategies. 2. payoff: a function assigning to each player i : Player and each strategy profile (a dependent function (j : Player) → Strategy j choosing a strategy for every player) a real number ℝ representing that player's payoff.

Written by a model that saw only the Lean, never the English above. If the two disagree, that is worth a challenge.

Lean source view module on GitHub

/-- A strategic-form (normal-form) game with player type `Player`. -/
structure StrategicGame (Player : Type*) where
  Strategy : Player → Type*
  payoff : (i : Player) → (∀ j, Strategy j) → ℝ
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