proposition: Lemma component_can_e' : cancel component_e' component_e.
proof: Proof. move => x; rewrite /component_e/component_e'; by case (decE _). Qed.
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)