proposition: Lemma inspos_lt_size_ins : pos < size ins.
proof: Proof. Proof using. rewrite /ins size_set_nth /maxn. by case (ltnP pos.+1 (size Row)); first exact: ltnW. Qed.
imports: HB(structures) mathcomp(all_ssreflect) mathcomp(perm fingroup) tools partition Yamanouchi ordtype subseq tableau std stdtab