proposition: Lemma mx0_is_trig m n : is_trig_mx (0 : 'M[V]_(m, n)).
proof: Proof. by apply/is_trig_mxP => i j _; rewrite mxE. 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)