proposition: Lemma gcdsr_dvdr : forall p, ((gcdsr p)%:P : poly_of R) %| p.
proof: Proof. move=> p; case: (gcdsr_primitive p)=> x [? _]; apply/dvdrP. by exists x; rewrite mulrC. 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)