It's Merriam-Webster's Word of the Day for June 26th.
Today's word is zero sum, spelled as two hyphenated words.
Zero sum is an adjective.
It describes something such as a gain, mentality,
or situation in which any gain corresponds directly with an equivalent loss.
Here's the word used in a sentence from The New York Times by Josh Katz.
Domestic migration is zero sum, meaning a loss of college graduates,
prized by local officials and tax collectors in Washington or San Francisco,
can be a gain for Kansas City or Orlando.
Does game theory sound like fun?
It can be
if you're a mathematician or economist who needs to analyze a competitive situation in which the outcome is determined by the choices of the players and chance.
Game theory was introduced by mathematician John von Neumann and economist Oscar Morgenstern in their 1944 book,
The Theory of Games and Economic Behavior.
In game theory, a zero-sum game is one, such as chess or checkers,
where each player has a clear purpose that is completely opposed to that of the opponent.
In economics,
a situation is zero-sum if the gains of one party are exactly balanced by the losses of another,
and no net gain or loss is created.
However, such situations in real life are rare.