Models of (horizontal) product differentiation generally admit many equilibria. These include concentrated equilibria, in which few firms each offer many products, and fragmented equilibria, in which many firms each offer one product. Since these outcomes depend in a delicate way on features of...

In a number of papers on their theory of Inequity Aversion, E. Fehr and K. Schmidt have claimed that the theory explains the behavior in many experiments. By virtue of having an infinite number of parameters the theory can predict a wide range of outcomes, from the competitive to the...

We examine an evolutionary model with "local interactions," so that agents are more likely to interact with some agents than with others. We first review the result that equilibrium strategy choices with given local interactions correspond to correlated equilibria of the underlying game. We then...