proposition: Lemma mxrank0 m n : \rank (0 : 'M_(m, n)) = 0%N.
proof: Proof. by apply/eqP; rewrite -leqn0 -(@mulmx0 _ m 0 n 0) mulmx_max_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)