proposition: Lemma mxrank1 n : \rank (1%:M : 'M_n) = n.
proof: Proof. exact: mxrank_unit. 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)