In this paper we consider a model of oligopolistic competition where firms make a two-dimensional product line decision. They choose a location in style space, thus inducing horizontal differentiation, and produce different qualities (a product line) of a given good (vertical differentiation),...

Armchair evidence shows that many industries are made of a few big commercial ormanufacturing firms, which are able to affect the market outcome, and of a myriad of smallfamily-run businesses with very few employees, each of which has a negligible impact on themarket. Examples can be found in...