We define social institutions as strategies in some repeated game. With this interpretation in mind, we consider the impact of introducing requirements on strategies which have been viewed as necessary properties for any social institution to endure. The properties we study are finite...

We consider a two-player game in which one player can take a costly action (i.e., to provide a favor) that is bene¯cial to the other. The game is in¯nitely repeated and each player is equally likely to be the one who can provide the favor in each period. In this context, equality matching is...

We present a simple proof of existence of subgame perfect equilibria in games with perfect information.

We present two simple proofs of existence of subgame perfect equi- libria in continuous games with perfect information.

We show that for any discount factor, there is a natural number M such that all subgame perfect equilibrium outcomes of the discounted repeated prisoners dilemma can be obtained by subgame perfect equilibrium strategies with the following property: current play depends only on the number of the...

We characterize Nash equilibria of games with a continuum of players (Mas-Colell (1984)) in terms of approximate equilibria of large finite games. For the concept of ("; ") equilibrium in which the fraction of players not " optimizing is less than " we show that a strategy is a Nash equilibrium...

We present a puri¯cation result for incomplete information games with a large ¯nite number of players that allows for compact metric spaces of actions and types. This result is then used to generalize the puri¯cation theorems of Schmeidler (1973), Rashid (1983) and Kalai (2004). Our proofs...

We observe many episodes in which a large number of people attempt to withdraw their deposits from a bank, forcing it to suspend withdrawals or even to fail. In contrast with the view that those episodes are driven by consumers panic or sunspots, we propose to explain them as a consequence of...

We show that a strategy is a Nash equilibrium in a game with a continuum of players if and only if there exists a sequence of finite games such that its restriction is an "n-equilibria, with "n converging to zero. In our characterization, the sequence of finite games approaches the continuum...