A subset of a game that can be considered a game in its own right(noun)
A minor or incidental game within a larger video game; a minigame.(noun)
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Use "subgame" in a sentence
"It can be expressed by saying that the strategy-pair is a nash equilibrium for every subgame of the original game, where a subgame is the result of taking a node of the original game tree as the root, pruning away everything that does not descend from it."
"Other participants selections provided results that were consistent with the trust and reciprocity effects observed in the 1995 Berg, Dickhaut, and McCabe experiment, in contrast with the subgame-perfect equilibrium expected by neoclassical economic assumptions."
"If there was a subgame involving bikini models we'd really be talking, but there isn't, so shut up."