Communication, correlation, and symmetry in bargaining

Abstract This paper considers two-player normal form games where each player can send a payoff-irrelevant message prior to play. Let G be the game without communication, and G ∗ ( M ) the extended game with message set M . Any convex combination of Nash outcomes in G can be approximated in a subgame perfect equilibrium of G ∗ ( M ) for some M . Furthermore, every symmetric game has a symmetric subgame perfect communication equilibrium that is undominated in a limit sense as the message set is enlarged.