proposition: Lemma map_mx_is_scalar n (A : 'M_n) : is_scalar_mx A^f = is_scalar_mx A.
proof: Proof. rewrite /is_scalar_mx; case: (insub _) => // i. by rewrite mxE -map_scalar_mx inj_eq //; apply: map_mx_inj. 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)