Two-player repeated games with nonobservable actions and observable payoffs

This paper studies two-person repeated games in which after each stage a player is informed about the payoff he received at the previous stage. The information can, in some cases, include more than that. Four kinds of Nash-equilibrium concepts are defined by the limit of the means. A characterization of the equilibrium-payoffs sets and several properties of these sets are given. As a specific example, the standard information case, that of the folk theorem, is provided.