proposition: Lemma submx1 m n (A : 'M_(m, n)) : (A <= 1%:M)%MS.
proof: Proof. by rewrite submx_full // row_full_unit unitmx1. 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 finalg zmodp matrix)