This paper considers the robustness of optimal decisions in a model of monopoly and a model of competitive equilibrium in a securities market. Robustness, defined as payoffs being continuous with respect to perturbations in the underlying model, fails to hold for either model. Decision rules are...

In a number of evolutionary models the presence of mutations, or random components of choice, serve to refine predictions of long-run behavior. We analyze the effects of mutation rates that vary because of the presence of imitation. A full characterization of long-run outcomes is provided for...

Limitations in agents’ ability to observe, measure and compute are studied. A formulation in terms of induced changes in the players’ subjective perception of the game makes it possible to study these phenomena on a common footing with objective variation in the game. We study a model where...