Surjection

Noun

1. A function for which every element of the codomain is mapped to by some element of the domain; (formally) Any function f : X →<!-- → --> Y {\displaystyle f:X\rightarrow Y} for which for every y ∈<!-- ∈ --> Y {\displaystyle y\in Y} , there is at least one x ∈<!-- ∈ --> X {\displaystyle x\in X} such that f ( x ) = y {\displaystyle f(x)=y} .