proposition: Lemma sub1mx m n (A : 'M_(m, n)) : (1%:M <= A)%MS = row_full A.
proof: Proof. apply/idP/idP; last exact: submx_full. by move/mxrankS; rewrite mxrank1 col_leq_rank. 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)