In the prisoners' dilemma game, the only evolutionary stable strategy is defection, even though nutual cooperation yields a higher payoff. Building on a paper by Robson (1990), we introduce mutants who have the ability to send a (costly) signal, i.e., the "secret handshake," before each round of...

A population of players of players is randomly matched to play a normal form game G. The payoffs in this game represent the fitness associated with the various outcomes. Each individual has preferences over the outcomes in the game and chooses an optimal action with respect to those preferences....

We study equilibria in second price auctions when bidders are independently and privately informed about both their values and participation costs and their joint distributions across bidders are not necessarily identical. We show that there always exists an equilibrium in this general setting...

We investigate efficiency properties of sealed-bid second-price auctions with costly participation and resale. Each bidder chooses to participate in the auction if her valuation is higher than her optimally chosen participation cutoff. If resale is not allowed and the bidder valuations are drawn...

The payoff matrix of a finite stage game is realized randomly, and then the stage game is repeated infinitely. The distribution over states of the world (a state corresponds to a payoff matrix) is commonly known, but players do not observe nature’s choice. Over time, they can learn the state...

We characterize perfect public equilibrium payoffs in dynamic stochastic games, in the case where the length of the period shrinks, but players' rate of time discounting and the transition rate between states remain fixed. We present a meaningful definition of the feasible and individually...

We characterize an optimal mechanism for a seller with one unit of a good facing N ≥ 3 buyers and a single competitor who sells another identical unit in a second-price auction. Buyers who do not get the seller's good compete in the competitor's subsequent auction. The mechanism features...