proposition: Lemma scalar_mx_is_trig a : is_trig_mx (a%:M).
proof: Proof. by rewrite is_diag_mx_is_trig// scalar_mx_is_diag. 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)