In game theory, perhaps the most important category of simple games is

something called *zero sum games*. It's also one of those mathematical

things that are widely abused by the clueless - you *constantly* hear

references to the term "zero-sum game" in all sorts of contexts, and they're

almost always *wrong*.

A zero-sum game is a game in which the players are competing for resources, and the set of resources is fixed. The fixed resources means that any gain by one player is necessarily offset by a loss by another player. The reason that this is called

zero-sum is because you can take any result of the game, and "add it up" - the losses will always equal the wins, and so the sum of the wins and losses in the result of the game will always be 0.