proposition: Lemma map_addsmx m1 m2 n (A : 'M_(m1, n)) (B : 'M_(m2, n)) : (((A + B)%MS)^f :=: A^f + B^f)%MS.
proof: Proof. by apply/eqmxP; rewrite !addsmxE -map_col_mx !map_submx !addsmxE andbb. 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)