Equivalence Class Equivalent Statements/3 iff 5

Theorem
Let $\RR$ be an equivalence relation on $S$.

Let $x, y \in S$.


 * $x \mathrel \RR y$
 * $y \in \eqclass x \RR$

Proof
This follows through dint of the symmetry of $\RR$ and the definition of Equivalence Class.