Wikipedia disagrees with you: https://en.wikipedia.org/wiki/Zero-sum_game
a mathematical representation of a situation in which each participant’s gain or loss of utility is exactly balanced by the losses or gains of the utility of the other participants.
Emphasis mine.
(By your definition, it seems to me that almost everything would be zero sum. If I bake a tasty cake for my friends, and that causes one of them to not visit the bakery that evening, the baker has lost out. More generally, see my post “Pareto improvements are rarer than they seem”: https://www.lesswrong.com/posts/5AQBNwDoKW5YXDbvc/pareto-improvements-are-rarer-than-they-seem)
Wikipedia disagrees with you: https://en.wikipedia.org/wiki/Zero-sum_game
Emphasis mine.
(By your definition, it seems to me that almost everything would be zero sum. If I bake a tasty cake for my friends, and that causes one of them to not visit the bakery that evening, the baker has lost out. More generally, see my post “Pareto improvements are rarer than they seem”: https://www.lesswrong.com/posts/5AQBNwDoKW5YXDbvc/pareto-improvements-are-rarer-than-they-seem)