fact: Definition eqmx F m1 m2 n (A : 'M[F]_(m1, n)) (B : 'M_(m2, n)) := prod (\rank A = \rank B) (forall m3 (C : 'M_(m3, n)), ((A <= C) = (B <= C)) * ((C <= A) = (C <= B)))%MS.
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)