linguistic:voice_change
In mathematics, the sign function or signum function (from signum, Latin for "sign") is a function that has the value − 1, +1 or 0 according to whether the sign of a given real number is positive or negative, or the given number is itself zero. In mathematical notation the sign function is often represented as sgn x {\displaystyle \operatorname {sgn} x} or sgn (x) {\displaystyle \operatorname {sgn}(x)}.