One-Shot Versus Continuous Interaction in Oligopoly Games

This article is about the interpretation of Nash equilibria of one-shot oligopoly games in competition analysis. Such equilibria are often understood as steady-state equilibria of the corresponding game with continuous interaction between the market players. In my view, such interpretations are misguided. In one-shot games assuming the other players keep their strategies fixed, as the Nash equilibrium does, is a rational device for profit maximization. In a setting with continuous interaction it is only rational if the assumption remains rational when the other players are given a chance to adjust their choices. That is seldom the case.