Binary function

In mathematics, a binary function (also called bivariate function, or function of two variables) is a function that takes two inputs.

Precisely stated, a function ${\displaystyle f}$ is binary if there exists sets ${\displaystyle X,Y,Z}$ such that

${\displaystyle \,f\colon X\times Y\rightarrow Z}$

where ${\displaystyle X\times Y}$ is the Cartesian product of ${\displaystyle X}$ and ${\displaystyle Y.}$