In (5) a solution concept for extensive-form games was introduced, called perfect Bayesian equilibrium (PBE), and shown to be a strict refinement of subgame-perfect equilibrium; it was also shown that, in turn, sequential equilibrium (SE) is a strict refinement of PBE. In (6) the notion of PBE...

In principle, anything that a player can do to communicate and coordinate with other players could be described by moves in an extensive-form game, so that planning these communication moves would become part of the player's strategy choice itself. Adding a communication system does not...