Non-Reflexive Relation/Examples/Arbitrary Non-Reflexive Relation 2

Example of Non-reflexive Relation
Let $S = \set {a, b}$.

Let $\RR$ be the relation on $S$ defined as:
 * $\RR = \set {\paren {a, a} }$

Then $\RR$ is neither:
 * a reflexive relation, as $\tuple {b, b} \notin \RR$

nor:
 * an antireflexive relation, as $\tuple {a, a} \in \RR$

Thus $\RR$ is a non-reflexive relation.