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Rock-Paper-Scissors


Rock-paper-scissors is a simultaneous two-player zero-sum game in which rock defeats scissors, scissors defeats paper, and paper defeats rock. Assigning payoff 1 to a win, -1 to a loss, and 0 to a tie gives the row player's payoff matrix

 A=(0 -1 1; 1 0 -1; -1 1 0),
(1)

with the rows and columns ordered as rock, paper, and scissors.

The game has no Nash equilibrium in pure strategies. Its unique mixed-strategy Nash equilibrium assigns probability 1/3 to each action, and its game value is 0.


See also

Mixed Strategy, Nash Equilibrium, Payoff Matrix, Zero-Sum Game

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References

Osborne, M. J. and Rubinstein, A. A Course in Game Theory. Cambridge, MA: MIT Press, 1994.

Cite this as:

Weisstein, Eric W. "Rock-Paper-Scissors." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/Rock-Paper-Scissors.html

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