# Multivalued function

A multivalued function (multifunction) is a relation like a function. A multifunction associates each input with at least one output.[1] A strict function associates each input with exactly one output. An example of a multivalued function is the square root. Every complex number (except for 0), has two square roots. Example: ${\displaystyle {\sqrt {4}}}$ could be 2 or -2 because ${\displaystyle 2^{2}=4}$ and ${\displaystyle (-2)^{2}=4}$.