Rel, bicategory of relations, allegory
left and right euclidean;
extensional, well-founded relations.
A (binary) relation $\sim$ on a set $A$ is reflexive if every element of $A$ is related to itself:
In the language of the $2$-poset Rel of sets and relations, a relation $R: A \to A$ is reflexive if it contains the identity relation on $A$:
A set with a reflexive relation is the same as a loop digraph $(V, E, s:E \to V, t:E \to V)$ with function $refl:V \to E$ such that
reflexive relation, irreflexive relation
Last revised on July 21, 2023 at 10:45:18. See the history of this page for a list of all contributions to it.