subgame
Noun
Meaning
(game theory) A subset of a game that can be considered a game in its own right
(video games) A minor or incidental game within a larger video game; a minigame.
Source: en.wiktionary.orgSynonyms
Examples
For such games the subgame perfect Nash equilibrium may be more meaningful as a tool of analysis.
If player one goes right the rational player two would de facto be kind to him in that subgame.
It would be useful if each subgame could be analyzed separately, and then the results combined to give an analysis of the entire game.
The blue equilibrium is not subgame perfect because player two makes a non-credible threat at 2(2) to be unkind (U).
The image to the right shows a simple sequential game that illustrates the issue with subgame imperfect Nash equilibria.
The Nash equilibrium is a superset of the subgame perfect Nash equilibrium.