Two-person repeated games with no discounting are considered where there is uncertainty about the type of the players. If there is a possibility that a player is an automaton committed to a particular pure or mixed stage -game action, then this provides a lower bound on the Nash equilibrium payoffs to a normal type of this player. The lower bound is the best available and is robust to the existence of other types. The results are extended to the case of two-sided uncertainty. This work extends Schmidt (1993) who analysed the restricted class of conflicting interest games.

We show that, in repeated common interest games without discounting, strong ‘perturbation implies efficiency’ results require that the perturbations must include strategies that are ‘draconian’ in the sense that they are prepared to punish to the maximum extent possible. Moreover, there is a draconian strategy whose presence in the perturbations guarantees that any equilibrium is efficient. We also argue that the results of Anderlini and Sabourian (1995) using perturbation strategies that are cooperative (and hence nondraconian) are not due to computability per se but to the further restrictions they impose on allowable beliefs.

The authors consider a repeated game between two long-run players, one of whom is relatively patient. Each player has a small amount of uncertainty about the other's strategy. Given a weak assumption about the support of this uncertainty, the more patient player obtains (in any Nash equilibrium) approximately the highest payoff consistent with the individual rationality of the other player, if the latter is patient enough. If the less patient player is relatively impatient, any Nash equilibrium gives the more patient player at least the Stackelberg payoff: this generalizes K. M. Schmidt's (1993) result, which applies only to games of conflicting interests.