An equilibrium, (or Nash equilibrium, named after John Nash) is a set of strategies, one for each player, such that no player has incentive to unilaterally change her action.
Players are in equilibrium if a change in strategies by any one of them would lead that player to earn less than if she remained with her current strategy.
For games in which players randomize (mixed strategies), the

*expected*or average payoff must be at least as large as that obtainable by any other strategy.updated: 15 August 2005

HOW TO CITE THIS ENTRY

- To learn more:
- Try the normal-form game solver to automatically calculate equilibria on the applets page.
- Take an online quiz on finding equilibria in games.