We study the percentage of welfare losses (PWL) yielded by imperfect competition under product differentiation. When demand is linear, if prices, outputs, costs and the number of firms can be observed, PWL is arbitrary in both Cournot and Bertrand equilibria. If in addition, the elasticity of...

In this paper we provide necessary and sufficient conditions for the existence of a Cournot equilibrium when demand is rho-linear and firms are identical and produce under constant returns to scale. We focus on inelastic and convex demand which yields non concave profit functions.We show that...