This paper proves the existence of a symmetric equilibrium with multiproduct firms using a nested logit model of demand. The demand model is parameterized by two variables that characterize different dimensions of preference for variety. These reflect intragroup heterogeneity and intergroup...

The authors propose a specific characteristics framework in order to construct linkages between alternative approaches to modeling product differentiation. It is shown that a demand system that satisfies the gross substitutes property imposes specific requirements on the locations of products....