Definition#
Let \(\rho\) be a relation on \(S\). We say that \(\rho\) is reflexive if \(a\rho a\) for all \(a \in S\).
Example#
On \(\mathbb{Z}\), the relation \(\leq\) is reflexive, but not \(\lt\) is not.
Source#
Gregory T. Lee. Abstract Algebra. 1st ed. Springer Cham, 2018. pp. 5.
