fact: Definition is_edge e x u y := e \in eset G /\ [/\ endpt G false e = x, endpt G true e = y & le G e ≡ u].
imports: HB(structures) Coq(Relation_Definitions Morphisms RelationClasses) mathcomp(all_ssreflect) GraphTheory(edone finite_quotient preliminaries bij equiv) GraphTheory(setoid_bigop structures pttdom rewriting) GraphTheory(finmap_plus)