In this paper we consider a model of group formation where group of individuals may have different feasible sets. We focus on two polar cases, increasing returns, when the set of feasible alternatives increases if a new member joins the group, and decreasing returns, when a new member has an...

All agents have the same ordinal ranking over all objects, receiving no object (opting out) may be preferable to some objects, agents differ on which objects are worse than opting out, and the latter information is private. The Probabilistic Serial assignment, improves upon (in the Pareto sense)...

This paper examines the conditions which guarantee that the set of coalition-proof Nash equilibria coincides with the set of strong Nash equilibria in the normal form games without spillovers. We find that population monotonicity properties of the payoff functions, when the payoff of a player...

This paper examines a model of an infinite production economy with a finite number of types of agents and semi-public goods, which are subjected to crowding and exclusion. The utility of an agent depends not only on the vector of public commodities produced by the coalition to which she belongs,...

This paper examines a model of an infinite production economy with a finite number of types of agents and semi-public goods, which are subjected to crowding and exclusion. The utility of an agent depends not only on the vector of public commodities produced by the coalition to which she belongs,...