proposition: Lemma mxrank_leqif_eq m1 m2 n (A : 'M_(m1, n)) (B : 'M_(m2, n)) : (A <= B)%MS -> \rank A <= \rank B ?= iff (A == B)%MS.
proof: Proof. by move=> sAB; rewrite sAB; apply: mxrank_leqif_sup. 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)