proposition: Lemma stableDmx : stablemx V f -> stablemx W f -> stablemx (V + W)%MS f.
proof: Proof. by move=> fV fW; rewrite addsmxMr addsmxS. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype finfun bigop finset fingroup perm order) mathcomp(div prime binomial ssralg finalg zmodp matrix)