Escape from a prisoners' dilemma by communication with a trusted third party

We present a game theoretic coordination mechanism in a multi agent community. We assume that all the agents are rational and have the ability to communicate with each other. In our approach, agents are treated as players in a noncooperative game defined in conventional game theory. In order to make the agents behave coordinately and to avoid an undesirable state, such as Prisoners' dilemma, we introduce a trusted third party into the conventional two-player game theory. The mechanism changes the equilibrium states by altering the payoff of the game. We show how agents are able to recognize undesirable states by reasoning on a 2 by 2 payoff matrix and find a way out by communicating with a trusted third party. A communication protocol among agents and the trusted third party is constructed to achieve a negotiation for coordination.