proposition: Lemma all_comm_mx1 f : all_comm_mx [:: f].
proof: Proof. by rewrite /comm_mxb all2rel1. 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)