A zero-sum or constant-sum game is one in which the parties view conflict as a fixed pie - where one party wins, the other must lose.

Zero-Sum Game

A theoretical situation in negotiation or conflict where one party's gain is directly proportional to another's loss, leaving no net benefit.

Constant-Sum Game

A situation in decision theory where the total payoff to all players remains constant regardless of the strategies employed, implying that any gain by one party directly corresponds to a loss by another.