Definition:Quasi-Reflexive Relation/Definition 1

Definition

Let $\RR \subseteq S \times S$ be a relation in $S$.

$\RR$ is quasi-reflexive if and only if:

$\forall x, y \in S: \tuple {x, y} \in \RR \implies \tuple {x, x} \in \RR \land \tuple {y, y} \in \RR$

Also see

• Equivalence of Definitions of Quasi-Reflexive Relation

• Definition:Left Quasi-Reflexive Relation
• Definition:Right Quasi-Reflexive Relation

• Results about quasi-reflexive relations can be found here.