Type correlated equilibria for games with payoff uncertainty

Summary Aumann's notion of correlated equilibrium is extended to games with payoff uncertainty. A type correlated equilibrium is a correlated equilibrium for Harsanyi's game in player-types. An equivalent definition is a probability distribution over types and actions which is consistent with the prior distribution over types, such that when each player observes its type and action, the observed action is optimal and no further information about other players' types is obtained. Any such equilibrium can be implemented by a type-independent correlation device when players' observations may be type-dependent. The type correlated equilibrium correspondence is shown to be upperhemicontinuous with respect to player information.Support from NSF grant IRI-8609208 is gratefully acknowledged. I am grateful to Maxwell Stinchcombe for comments on an earlier draft of this paper. Any remaining errors are my own.