absolute margin. We derive these results in both a monopoly model and a variety of different competitive models. We conclude …

This paper investigates how the tying of complementary products can be used to preserve and extend monopoly positions …. We first show how a firm that is a monopolist of a product in the current period can use tying to preserve its monopoly … monopoly position into a newly emerging market. The analysis focuses on the importance of entry costs and network externalities …

marginal costs nonparametrically, allow for unobserved firm heterogeneity, and nest a variety of equilibrium oligopoly models …) intuition for empirically discriminating between alternative models of oligopoly competition …

from trade under Bertrand and Cournot oligopoly. Firms differentiate their products to mitigate competition, but only if … levels of investment can raise Bertrand profit above Cournot profit and also above the monopoly profit at autarky when …