proposition: Lemma rank_row_mx0 m n p (A : 'M_(m, n)) : \rank (row_mx A (0 : 'M_(m, p))) = \rank A.
proof: Proof. by rewrite -mxrank_tr -[RHS]mxrank_tr tr_row_mx trmx0 rank_col_mx0. 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)