An Equivalence [[Relation]] is a a form of [[Binary Relation]] that satisfies certain rules that are used to describe 'equivalence' within an algebra / space.
$\huge a \sim b $
For a [[Binary Relation]] $R$ on the [[Set|set]] $X$ to be an equivalence relation, it must satisfy the [[Transitive Property]], [[Reflexive Property]] and the [[Symmetric Property]].
$ \huge \begin{align}
a \sim a \\
a\sim a &\iff a \sim a\\
a \sim b \wedge b\sim c &\implies a \sim c
\end{align} $
Under an equivalence relation, many objects that are not necessarily strictly *equal* may be considered equivalent. All objects in $X$ that are equivalent form an [[Equivalence Class]] under $R$.