proposition: Lemma is_row_Sch w : is_row (Sch w).
proof: Proof. Proof using. by elim/last_ind: w => [// | w wn IHw]; rewrite Sch_rcons is_row_ins. Qed.
imports: HB(structures) mathcomp(all_ssreflect) mathcomp(perm fingroup) tools partition Yamanouchi ordtype subseq tableau std stdtab