proposition: Lemma genmx_id m n (A : 'M_(m, n)) : (<<<<A>>>> = <<A>>)%MS.
proof: Proof. exact/eq_genmx/genmxE. 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)