# equality of games

In combinatorial game theory, equality of games is a defined concept. It certainly doesn't coincide with the idea of having the same game (what you could call an identical copy).

Firstly one has an ordering of games, such that G >= H is a relation defined to hold just when the difference game G - H >= 0.

Then two games G and H are by definition **equal** when G >= H and H >= G.

This is an obvious definition to make, from a mathematical point of view. One also wants to be able to compute with this idea. The theory of canonical forms of games is designed to do that.

Two equal games G and H have the basic property that in a sum of games, one can be replaced by the other, without changing the overall outcome (win or loss).