proposition: Lemma gcdsr_mulX : forall p, gcdsr (p * 'X) %= gcdsr p.
proof: Proof. by move=> p; rewrite -[p*'X]addr0 gcdsr_gcdl gcd0r. 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)