proposition: Lemma col0 m n j0 : col j0 (0 : 'M_(m, n)) = 0.
proof: Proof. exact: col_const. 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)