Symmetric equilibrium
Symmetric equilibrium
In game-theory, a symmetric equilibrium is an equilibrium where all players use the same strategy (possibly mixed) in the equilibrium. In the prisoner's-dilemma game pictured to the right, the only nash-equilibrium is (D, D). Since both players use the same strategy, the equilibrium is symmetric.
Symmetric equilibria have important properties. Only symmetric equilibria can be evolutionarily-stable-states in single population models.