proposition: Lemma morph_modp (F : fieldType) (p : {poly F}) : {morph (fun x : {poly F} => x %% p) : x y / x + y}.
proof: Proof. move=> x y; by rewrite modpD. Qed.
imports: mathcomp(all_ssreflect fingroup perm ssralg zmodp) mathcomp(matrix mxalgebra poly polydiv mxpoly) ssralg_ext