Definition:Serial Relation

Definition
Let $\mathcal R \subseteq S \times S$ be a relation in $S$.

$\mathcal R$ is serial :


 * $\forall x \in S: \exists y \in S: \tuple {x, y} \in \mathcal R$

That is, a relation $\mathcal R \subseteq S \times S$ is serial every element of $S$ relates to some other element of $S$.

Also see

 * Left-Total Relation