Definition:Retraction

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Definition

Let $\mathbf C$ be a metacategory.

Let $f: C \to D$ be a morphism of $\mathbf C$.


A retraction of $f$ is a morphism $g: D \to C$ such that:

$g \circ f = \operatorname{id}_C$


Retract

Let $g: D \to C$ be a retraction of $f$.


Then $D$ is said to be a retract of $C$.


Also see


Sources