Combinatorial game theory (CGT) is a branch of applied mathematics and theoretical computer science that typically studies sequential games with perfect information. Study is largely confined to two-player games which have a position in which the players take turns changing in defined ways or moves to achieve a defined winning condition. CGT has not traditionally studied games randomness and imperfect or incomplete information (sometimes called games of chance, like poker), favoring games whose position is public to both players, and in which the set of available moves is also public (perfect information). Combinatorial games include well-known games like chess, checkers, Go, Arimaa, Hex, and Connect6. They also include one-player combinatorial puzzles, and even no-player automata, like Conway's Game of Life. In CGT, the moves in these games are represented as a game tree.