Non-cooperative game theory
In game theory, the non-cooperative game is a game with competition between individual players, as opposed to cooperative games, together with in which alliances can only operate if self-enforcing e.g. through credible threats. However, 'cooperative' & 'non-cooperative' are only technical terms to describe the concepts used to good example a game, so it is possible to ownership cooperative game theory to service example competition and using non-cooperative game theory to good example cooperation.
The key distinguishing feature is the absence of external rule to instituting rules enforcing cooperative behavior. In the absence of external advice such as contract law, players cannot institution into coalitions and must compete independently.
Negative-sum game and Zero-sum game are both species of non-cooperative games.