\begin{definition}[Definition:Right Inverse Mapping]
Let $S, T$ be sets where $S \ne \O$, that is, $S$ is not empty.
Let $f: S \to T$ be a mapping.
Let $g: T \to S$ be a mapping such that:
:$f \circ g = I_T$
where:
:$f \circ g$ denotes the composite mapping $g$ followed by $f$
:$I_T$ is the identity mapping on $T$.
Then $g: T \to S$ is called '''a right inverse (mapping) of $f$'''.
\end{definition}