proposition: Lemma is_scalar_mx_is_trig A : is_scalar_mx A -> is_trig_mx A.
proof: Proof. by move=> /is_scalar_mx_is_diag /is_diag_mx_is_trig. 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)