 Combinatorial game theory

Combinatorial game theory studies positions in alternating-move games with fully specified legal moves, usually perfect information and no chance. A position can be defined recursively by the positions available to each player. Under the normal-play convention, a player with no legal move loses.

An impartial game gives both players the same moves; Nim is the standard example. A partizan game allows different moves for Left and Right. The disjunctive sum lets a player move in exactly one component on each turn, making it possible to study how game positions combine algebraically. Infinite play or misère play requires additional conventions; normal-play results do not automatically transfer.

Combinatorial game theory is a branch of mathematics and theoretical computer science that studies games with perfect information, where two players take turns making moves and there is no element of chance. It focuses on two-player games that are typically played to a conclusion, meaning that the game ends in a win, loss, or draw. Examples of such games include chess, Go, Nim, and various other abstract and strategic games.