A collaborative filtering system recommends to users products that similar users like. Collaborative fi ltering systems influence purchase decisions, and hence have become targets of manipulation by unscrupulous vendors. We provide theoretical and empirical results demonstrating that while...

Oblivious equilibrium is a new solution concept for approximating Markov perfect equilibrium in dynamic models of imperfect competition among heterogeneous firms and has recently been used in multiple economic studies. In this paper, we present algorithms for computing oblivious equilibrium and...

We characterize environmental quality as a stock, and its rate of deterioration as a flow. We consider a class of problems, which we call "SFQ" problems, in which both stocks and flows can be controlled to promote the quality of a resource stock. Abatement (curbing the flow) and restoration...

This paper explores the connection between three important threads of economic research offering different approaches to studying the dynamics of an industry with heterogeneous firms. Finite models of the form pioneered by Ericson and Pakes (1995) capture the dynamics of a finite number of...