Title. Multiplayer Rock-Paper-Scissors
Speaker. Charlotte Aten
Institution. Department of Mathematics, University of Rochester, Rochester, NY
Abstract. The game of Rock-Paper-Scissors (RPS) involves two players simultaneously choosing either rock, paper, or scissors. Informally, the rules of the game are that “rock beats scissors, paper beats rock, and scissors beats paper”. That is, if one player selects rock and the other selects paper then the latter player wins, and so on. If two players choose the same item then the round is a tie.
It is folklore that the only “valid” RPS variants for two players use an odd number of items. Currently this is mentioned on the Wikipedia entry for Rock-Paper-Scissors without citation and with a reference to a collection of such games. In our language we have the following result. We give a proof of a more general statement.