On the Equivalence of Nash and Evolutionary Equilibrium in Finite Populations

This paper provides sufficient and partially necessary conditions for the equivalence of Nash and evolutionary equilibrium in symmetric games played by finite populations. The focus is on symmetric equilibria in pure strategies. The conditions are based on properties of the payoff function that generalize the constant-sum property and the ”smallness” property, the latter of which is known from models of perfect competition and non-atomic, anonymous, or large games. The conditions are illustrated on examples of Bertrand and Cournot oligopoly games.