\begin{definition}[Definition:Coreflexive Relation/Definition 1]
Let $\RR \subseteq S \times S$ be a relation in $S$.
$\RR$ is '''coreflexive''' {{iff}}:
:$\forall x, y \in S: \tuple {x, y} \in \RR \implies x = y$
\end{definition}