Econometrica: Nov, 1990, Volume 58, Issue 6

Universal Mechanisms

https://doi.org/0012-9682(199011)58:6<1341:UM>2.0.CO;2-Z
p. 1341-1364

Francoise Forges

A scheme of plain conversation is constructed, which is a universal mechanism for all noncooperative games with incomplete information with at least four players, in the following sense: every solution which can be achieved by means of an arbitrary communication mechanism is a correlated equilibrium payoff of the game extended by the scheme of plain conversation; the corresponding equilibrium strategies use only finite sets of messages. By a property of the correlated equilibrium, a similar result holds also with the Nash equilibrium solution concept. The scheme of plain conversation is universal because it does not depend on the specification of the game, nor on the solution to achieve and it is easily implemented in any institutional context. The main proposition of this paper states that it can be used without any loss of efficiency. Some results are also available for three and two person games.