# Category:Surjections

This category contains results about Surjections.
Definitions specific to this category can be found in Definitions/Surjections.

Let $S$ and $T$ be sets or classes.

Let $f: S \to T$ be a mapping from $S$ to $T$.

$f: S \to T$ is a surjection if and only if:

$\forall y \in T: \exists x \in \Dom f: \map f x = y$

That is, if and only if $f$ is right-total.