Economics Department of the University of Pennsylvania Institute of Social and Economic Research -- Osaka University

Abstract

Industrial organization models commonly employ the Cournot equilibrium concept but often only the symmetric equilibria are considered. This is unsatis- factory when performing comparative statics unless it can be shown that no other (stable) equilibria exist. Problems may also arise in two-stage models in which firms, choosing capacity for example in the first stage, correctly anticipate a Cournot equilibrium outcome in the second stage. Some sufficient conditions for uniqueness of Cournot equilibrium are fairly well-known, but when the number of firms exceeds two, methods for finding all Cournot equilibria are not well-known. This note demonstrates how to find all n-firm Cournot equilibria.