We present a new approach to the theory of imperfect competition and apply it to study price competition among differentiated products. The central result provides general conditions under which there exists a pure strategy price equilibrium for any number of firms producing any set of products....

This paper analyzes price fixing by the Joint Executive Committee railroad cartel from 1880 to 1886 and develops tests of two game-theoretic models of tacit collusion. The first model, due to Abreu, Pearce and Stacchetti (1986), predicts that price will switch across regimes according to a...

We present a model of imperfect price competition where not all firms can sell to all consumers. A network structure models the local interaction of firms and consumers. We find that aggregate surplus is maximized with a fully connected network, which corresponds to perfect competition, and...