proposition: Lemma hookpartn_col d : hookpartn d 0 = colpartn d.
proof: Proof. apply val_inj; case: d => [|d]/=. by rewrite /hookpartn /colpartn -!lock. by rewrite /= hookpartnE // subn0 colpartnE. Qed.
imports: HB(structures) mathcomp(all_ssreflect) mathcomp(div ssralg ssrint ssrnum binomial) tools combclass sorted ordtype