proposition: Lemma hookpartn_row d : hookpartn d d.-1 = rowpartn d.
proof: Proof. apply val_inj; case: d => [|d]/=. by rewrite /hookpartn /rowpartn -!lock. by rewrite /= hookpartnE //= subnn /= rowpartnE. Qed.
imports: HB(structures) mathcomp(all_ssreflect) mathcomp(div ssralg ssrint ssrnum binomial) tools combclass sorted ordtype