Definition:Inverse Mapping/Definition 2

Definition

Let $f: S \to T$ and $g: T \to S$ be mappings.

Let:

$g \circ f = I_S$
$f \circ g = I_T$

where:

$g \circ f$ and $f \circ g$ denotes the composition of $f$ with $g$ in either order
$I_S$ and $I_T$ denote the identity mappings on $S$ and $T$ respectively.

That is, $f$ and $g$ are both left inverse mappings and right inverse mappings of each other.

Then:

$g$ is the inverse (mapping) of $f$
$f$ is the inverse (mapping) of $g$.

Also see

• Results about inverse mappings can be found here.