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