1.NounA related function that, given the output of the original function, returns the input that produced that output.
"In order for a function to have a left inverse it must be injective."
2.NounFor a given morphism f : X → Y, its right inverse (if it has one) is a morphism s : Y → X such that
s
∘
f
=
id
X
{\displaystyle s\circ f={\mbox{id}}_{X}}
.