fact: Definition adjacent (G : graph) (x y : G) := [exists e, e \in edges x y :|: edges y x].
imports: Coq(Setoid Morphisms) mathcomp(all_ssreflect) GraphTheory(edone finite_quotient bij preliminaries) GraphTheory(digraph sgraph treewidth minor checkpoint) GraphTheory(setoid_bigop structures mgraph mgraph2)