Min-max theorem

The min-max theorem is a way of finding the "optimal" answer to a problem. It says that no matter what choices your opponents make in a game, your best choice will always give you the best possible result. For example, if you're playing a game of Tic-Tac-Toe, the min-max theorem says that if you play your first move in the center square, you will always win or at least tie the game no matter what your opponent does.