ABSTRACT
J. C. Harsanyi was obliged to take recourse to the concept of “tacit bargaining,” supposedly engaged in by players who are rational and who regard other players as equally rational. Harsanyi’s argument in favor of equilibria as solutions to non-cooperative games is that they are self-enforcing. That is to say, their rationale does not depend on the players’ mutual trust, except for a belief in each other’s individual rationality, which, in turn, is defined in a way that excludes the notion of trust. Strategic analysis of two-person zero-sum games is especially simple, because these three principles of rational decision–the maximin principle, the equilibrium principle, and the sure-thing principle–are closely related. The use of mixed strategies is well known in games of strategy. A saddle point is an entry in a matrix of a two-person zero-sum game which is at the same time minimal in its row and maximal in its column.
