proposition: Lemma genmxP m1 m2 n (A : 'M_(m1, n)) (B : 'M_(m2, n)) : reflect (<<A>> = <<B>>)%MS (A == B)%MS.
proof: Proof. apply: (iffP idP) => eqAB; first exact: eq_genmx (eqmxP _). by rewrite -!(genmxE A) eqAB !genmxE andbb. 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)