proposition: Lemma comm0mx f : comm_mx 0 f.
proof: Proof. by rewrite /comm_mx mulmx0 mul0mx. 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)