zero sum

Zero sum describes situations where one party's gain exactly equals another's loss—the total never changes.

In game theory and economics, a zero-sum game has a fixed pool of resources: Poker is zero sum; every dollar won comes from another player's stack.

The term often appears in political and social contexts to characterize competitive thinking: He sees immigration as zero sum, as if every job taken by a newcomer is one lost by a native.

Not all competition is actually zero sum—trade and cooperation often expand the total.