proposition: Lemma xcol_const j1 j2 a : xcol j1 j2 (const_mx a) = const_mx a.
proof: Proof. exact: col_perm_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)