Nash equilibrium says:

Nash equilibrium? Nash equilibrium (named after John Forbes Nash, who proposed it) is a term used in game theory to describe equilibrium where each players strategy is optimal given the strategies of all other players. There is no unilateral profitable deviation from any of the players involved. In other words, no player in the game would take a different action as long as every other player remains the same. Nash equilibrium is self-enforcing b/c when players are at a Nash equilibrium, they have no desire to move b/c if they do, then they will be worse off.}