Game theory is a branch of mathematics that deals with decision making when there are multiple decision-makers, called “players”, and outcomes depend on the decisions of other players. Game theory is based on the metaphor of a game, in which the rules of play and the outcomes are well defined. The game metaphor is a very useful abstraction. Game theory is used to understand behavioral strategies in economics, evolutionary theory, politics, warfare and other domains. It is especially important for understanding how society works.

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