proposition: Lemma gcdp0 : right_id 0 gcdp.
proof: Proof. move=> p; have:= gcd0p p; rewrite /gcdp size_poly0 size_poly_gt0. by case: eqVneq => //= ->; rewrite eqxx. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop ssralg poly)