Coalition-proofness under weak and strong Pareto dominance

This article examines the structure of pure strategy coalition-proof Nash equilibria under weak and strong Pareto dominance in games with strategic complementarities and isotone externalities. The analysis is particularly focused on the following issues: (i) the inclusion relation between the set of coalition-proof Nash equilibria under weak Pareto dominance and the set of coalition-proof Nash equilibria under strong Pareto dominance; (ii) the conditions for the coincidence of the strong (resp. weak) Pareto dominance refinement and the coalition-proofness refinement under strong (resp. weak) Pareto dominance; (iii) the conditions for the uniqueness of a coalition-proof Nash equilibrium under both notions of Pareto dominance. Dual results are stated for games with antitone externalities.