On coalition-proof Nash equilibria in common agency games

In this paper we consider two notions of a coalitional deviation: strict de viation, where each of member of a deviating group is better off, and weak deviation, where at least one member of a deviating group is better off whi le all other members are at least as well off. We then examine, for the cla ss of common agency games introduced in Bernheim and Whinston (Quart. J. Ec on. 101 (1986), 1-31), the structure and properties of two notions of a coa lition-proof Nash equilibrium, generated by strict and weak deviation. We a lso study a relationship between coalition-proof equilibria, strong equilib ria, and Pareto undominated Nash equilibria. (C) 1999 Academic Press.