From Eva Koudela
Terence Kealey describes a “zero sum game” as that where everybody wins and nobody loses
(“Envy”, 28 March, p 26). This is the exact opposite of what “zero
sum” means in game theory. It denotes a “game” where any gain is offset by an
equal and opposite loss by some of the other players. So for every +x
there is −x, whose sum is 0, hence the term “zero sum”.
Terence Kealey writes: Your correspondent is quite right. I omitted the
prefix “non-” before “zero sum”. Sorry!
London
