proposition: Lemma pp_inj_dvdr : forall p q, p %| q -> pp p %| pp q.
proof: Proof. move=> p q; case/dvdrP=> x ->. by case/andP: (pp_mul x p)=>_; apply/dvdr_trans/dvdr_mull. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq) mathcomp(path choice fintype tuple finset ssralg) mathcomp(matrix poly) mathcomp(bigop polydiv) CoqEAL(stronglydiscrete dvdring)