Let $f:A\to B$ be a function.
A left inverse of $f$ is a function $g:B\to A$ such that $g\circ f(a) = a$ for all $a \in A$.
A right inverse of $f$ is a function $g:B\to A$ such that $f\circ g(b) = b$ for all $b\in B$.
An inverse of $f$ is a function $f^{-1}$ that is both a left and a right inverse of $f$.
Wikidata ID: Q191884