I model endogenous horizontal and vertical product differentiation with arbitrarily many heterogeneous firms. Firms are asymmetric in that they differ in their marginal costs. I prove that under an equilibrium refinement, all economically relevant firm outcomes are uniquely determined across all...

This paper develops tools and techniques to analyze the determinants of factor allocation and factor prices in economies with a large number of goods and factors. The main results of our paper characterize sufficient conditions for robust monotone comparative statics predictions in a Roy-like...