In the beginning of the second book of his Politeia (Republic) Plato in passage 2.358e-359a-c raises the issue of the administration of justice as a means of motivating people to behave fairly regarding their relationships and when cooperating with each other because, at the end, this is...

We study impersonal exchange, and ask how agents can behave honestly in anonymous transactions without contracts. We analyze repeated anonymous random matching games, where agents observe only their own transactions. Little is known about cooperation in this setting beyond the prisoner's...

The paper discusses community enforcement in infinitely repeated, two-action games with local interaction and uncertain monitoring. Each player interacts with and observes only a fixed set of opponents, of whom he is privately informed. The main result shows that when beliefs about the...

In the reputation literature, players have \emph{commitment types} which represent the possibility that they do not have standard payoffs but instead are constrained to follow a particular plan. In this paper, we show that arbitrary commitment types can emerge from incomplete information about...

We analyze the extent to which efficient trade is possible in an ongoing relationship between impatient agents with hidden valuations (i.i.d. over time), restricting attention to equilibria that satisfy ex post incentive constraints in each period. With ex ante budget balance, efficient trade...

Some private-monitoring games, that is, games with no public histories, can have histories that are almost public. These games are the natural result of perturbing public monitoring games towards private monitoring. We explore the extent to which it is possible to coordinate continuation play in...

I prove an efficiency result for repeated games with imperfect public monitoring in which one player's utility is privately known and evolves according to a Markov process. Under certain assumptions, patient players can attain approximately efficient payoffs in equilibrium. The public signal...

This paper extends the framework of Kajii and Morris (1997) to study the question of robustness to incomplete information in repeated games. We show that dynamically robust equilibria can be characterized using a one-shot robustness principle that extends the one-shot deviation principle. Using...

We provide a simple sufficient condition for the existence of a recursive upper bound on (the Pareto frontier of) the sequential equilibrium payoff set at a fixed discount factor in two-player repeated games with imperfect private monitoring. The bounding set is the sequential equilibrium payoff...