Editing Equivalence class (section)

==Graphical representation==
{{main|Cluster graph}}
[[File:Equivalentie.svg|thumb|160px|Graph of an example equivalence with 7 classes]]
An [[undirected graph]] may be associated to any [[symmetric relation]] on a set <math>X,</math> where the vertices are the elements of <math>X,</math> and two vertices <math>s</math> and <math>t</math> are joined if and only if <math>s \sim t.</math> Among these graphs are the graphs of equivalence relations. These graphs, called [[cluster graph]]s, are characterized as the graphs such that the [[Connected component (graph theory)|connected components]] are [[Clique (graph theory)|cliques]].{{sfn|Devlin|2004|p=123}}