proposition: Lemma comm_mx0 f : comm_mx f 0.
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)