We present a theory for why it might be rational for a platform to limit the number of applications available on it. Our model is based on the observation that even if users prefer application variety, applications often also exhibit direct network effects. When there are direct network effects,...

We propose a discrete-time exchange economy evolutionary model, in which two groups of agents are possibly characterized by heterogeneous preference structures. With respect to the classical Walrasian framework, in our setting the definition of equilibrium, in addition to utility functions and...

In the spirit of von Neumann and Morgenstern (1947), this paper provides an axiomatic representation of information. Under the von Neumann-Morgenstern axioms, along with an additional continuity, indifference to randomization, and a Blackwell informativeness axiom, I show that any ordering over...

We obtain exact necessary and sufficient conditions for existence and uniqueness of solutions of a class of homothetic recursive utility models postulated by Epstein and Zin (1989). The conditions center on a single test value with a natural economic interpretation. The test sheds light on the...

For mechanisms with two possible outcomes and a unique agent with two posible types, we state sufficient and necessary conditions over the type space that guarantees the existence of an incentive compatible mechanism. By using tropical geometry, we found that these conditions rely only on the...

We propose a class of multiple-prior representations of preferences under ambiguity where the belief the decision-maker (DM) uses to evaluate an uncertain prospect is the outcome of a game played by two conflicting forces, Pessimism and Optimism. The model does not restrict the sign of the DM's...