For many products, platforms enable sellers to transact with buyers. We show that the competitive conditions among sellers shape the market structure in platform industries. If product market competition is tough, sellers avoid competitors by joining different platforms. This allows platforms to...

We customize the aggregative game approach to oligopoly to study asymmetric media markets. Advertiser, platform, and consumer surplus are tied together by a simple summary statistic. When media are ad-financed and ads are a nuisance to consumers we establish see-saws between consumers and...

Two one-product firms compete in prices on a market with differentiated products. Goods are differentiated because customers switch from one good to the other at different relative prices. With the specification that mean demand in the market is unit-elastic 1 pro vide conditions on the shape of...

I present a class of address models of product differentiation with unit-elastic individual demand and show the existence of Nash equilibrium in prices under assumptions on utility functions and the taste and income heterogeneity across consumers. This paper complements the work by Caplin and...

For many products, platforms enable sellers to transact with buyers. We show that the competitive conditions among sellers shape the market structure in platform industries. If product market competition is tough, sellers avoid competitors by joining different platforms. This allows platforms to...

In a model of price competition single-product ¯rms compete for consumers. Consumerspurchase a variable quantity of one of the di®erentiated goods. The paper provides results onequilibrium existence when consumers are heterogeneous in their evaluation of the di®erentiatedgoods among each...