Let f:A→B be a function.
A left inverse of f is a function g:B→A such that g∘f(a)=a for all a∈A.
A right inverse of f is a function g:B→A such that f∘g(b)=b for all b∈B.
An inverse of f is a function f−1 that is both a left and a right inverse of f.
Wikidata ID: Q191884