proposition: Lemma map_mxM A B : (A *m B)^f = A^f *m B^f :> 'M_(m, p).
proof: Proof. apply/matrixP=> i k; rewrite !mxE rmorph_sum //. by apply: eq_bigr => j; rewrite !mxE rmorphM. 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 countalg finalg zmodp)