proposition: Lemma eqv_clot_hd (T: finType) (x y: T) (l: pairs T): eqv_clot ((x,y)::l) x y.
proof: Proof. apply: eqv_clot_pair. exact: mem_head. Qed.
imports: Coq(RelationClasses Setoid Morphisms) mathcomp(all_ssreflect) GraphTheory(preliminaries bij finite_quotient)