The growth of mobile applications on smartphones and tablets ("apps") ranks as one of the most astonishing technological developments of the recent past. The marketplaces for these mobile apps (i.e., the Apple iOS App Store and Google Play) are a significant disruptive change in the way content...

We consider dynamic oligopoly models in the spirit of Ericson and Pakes (1995). We introduce a new computationally tractable model for industries with a few dominant firms and many fringe firms, in which firms keep track of the detailed state of dominant firms and of few moments of the...