Let R ⊆ M × M {\displaystyle {}R\subseteq M\times M} be an equivalence relation, and let x ∈ M {\displaystyle {}x\in M} . Then
is called the equivalence class of x {\displaystyle {}x} with respect to R {\displaystyle {}R} .
![{\displaystyle {}[x]:={\left\{y\in M\mid (x,y)\in R\right\}}\,}](https://wikimedia.org/api/rest_v1/media/math/render/svg/bb2893f9a1fd41e58fda3ef2033bdae5213823f1)
