proposition: Lemma inspos_leq_size : pos <= size Row.
proof: Proof. Proof using. by elim: Row => [// | l0 r IHr] /=; case: (ltP l l0). Qed.
imports: HB(structures) mathcomp(all_ssreflect) mathcomp(perm fingroup) tools partition Yamanouchi ordtype subseq tableau std stdtab