Truel and triel are neologisms for a duel between three opponents, in which players can fire at one another in an attempt to eliminate them while surviving themselves.[1]
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Kilgour, D. Marc; Brams, Stephen J. (December 1997), "The Truel", Mathematics Magazine, 70 (5): 315–326, doi:10.2307/2691167, JSTOR2691167