Equivalence relation
Set
context | $X$ |
definiendum | $ \sim \in \text{EquivRel}(X) $ |
context | $ \sim \in \mathrm{Rel}(X) $ |
$x,y,z\in X$ |
postulate | $ x\sim x $ |
postulate | $ x\sim y \Leftrightarrow y\sim x $ |
postulate | $ x\sim y \land y\sim z \Leftrightarrow x\sim z $ |
Discussion
The relation $\sim$ is an equivalence relation, if it's in the intersection of all reflexive, all symmetric and all transitive relation. Hence
Reference
Wikipedia: Equivalence relation