AN EVOLUTIONARY INTERPRETATION OF MIXED-STRATEGY EQUILIBRIA

A convincing interpretation of mixed-strategy equilibria describes the m as steady states in a large population in which players use pure str ategies but the population as a whole mimics a mixed strategy. I study the conditions under which an evolutionary, stochastic learning proce ss converges to the appropriate distribution over pure strategies in t he population. I find that not all mixed equilibria can be justified a s the result of an evolutionary process even if the equilibrium is uni que. For symmetric 2 x 2 and 3 x 3 games I give necessary and sufficie nt conditions for convergence, which are related to the concept of an ESS, and for n x n games I give a sufficient condition. (C) 1997 Acade mic Press.