proposition: Lemma dotcnv x y: x·y ≡ (y°·x°)°.
proof: Proof. apply cnv_inj. by rewrite cnvdot cnvI. Qed.
imports: HB(structures) Coq(Setoid Morphisms) mathcomp(all_ssreflect) GraphTheory(edone preliminaries setoid_bigop structures)