proposition: Lemma oarc_loop e x y x' u u' : oarc G e x u y -> oarc G e x' u' x' -> x = y.
proof: Proof. case => Ee [[|]] [? ? ?]; case => _ [[|]] [? ? ?]; by subst. Qed.
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)