In a competitive-equilibrium analysis of giving to charity, we show that strategic complementarity between individual giving and aggregate giving can lead to multiple equilibria. This provides a possible explanation for observed heterogeneity in giving. It is possible, but not necessary, that at...

A tragedy of the commons appears when the users of a common resource have incentives to exploit it more than the socially efficient level. We analyze the situation when the tragedy of the commons is embedded in a network of users and sources. Users play a game of extractions, where they decide...

I provide two simple sufficient conditions under which the Pareto frontier of the Nash equilibrium set is coalition-proof. My first condition states there exists a pure-strategy Nash equilibrium which Pareto dominates all other serially undominated strategies. Under this condition, the...