proposition: Lemma dom_eqv_ : Proper (eqv ==> eqv) (dom : A -> A).
proof: Proof. by move=> x y xy; rewrite !domE xy. Qed.
imports: HB(structures) Coq(Setoid Morphisms) mathcomp(all_ssreflect) GraphTheory(edone preliminaries setoid_bigop structures pttdom)