proposition: Lemma flatmxOver {n : nat} {T : Type} (M : 'M[T]_(0, n)) S : M \is a mxOver S.
proof: Proof. by apply/mxOverP => - []. 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 countalg finalg zmodp)