proposition: Lemma scalar_mx_is_scalar a : is_scalar_mx a%:M.
proof: Proof. by apply/is_scalar_mxP; exists a. 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)