proposition: Lemma eq_mxcol n (A_ B_ : forall i, 'M[T]_(p_ i, n)) : (forall i, A_ i = B_ i) -> (\mxcol_i A_ i = \mxcol_i B_ i).
proof: Proof. by move=> /eq_mxcolP. 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)