When firms can supply several separate markets, collusion can take two forms. Either firms establish production quotas on all the markets, or they share markets. This paper compares production quotas and market sharing agreements in a Cournot duopoly where firms incur a fixed cost for serving...

We analyse the optimal pricing choice of an incumbent firm that sells a good with network externalities and is threatened by the entry of a higher quality variant. In the framework of a vertical differentiation model, we find a necessary and sufficient condition under which quality improvement...

In a model of horizontal product differentiation, we show that local monopolies may exist under free entry when capital is perfectly mobile. In contrast both with the situation of restricted entry and with the zero-profit approach to free entry outcomes of Salop (1979), the unit profit rate of...

In a model of horizontal product differentiation, we show that local monopolied may exist under free entry when capital is perfectly mobile. In contrast both with the situation of restricted entry and with the zero-profit approach to free entry outcomens of Salop 91979), the unit profit rate of...

We propose a general model of monopolistic competition, which encompasses existing models while being flexible enough to take into account new demand and competition features. The basic tool we use to study the market outcome is the elasticity of substitution at a symmetric consumption pattern,...