proposition: Lemma part_yam_of_stdtab t : is_stdtab t -> is_part (evalseq (yam_of_stdtab t)).
proof: Proof. move=> Htab; rewrite (shape_yam_of_stdtab Htab). apply: is_part_sht. by move: Htab; rewrite /is_stdtab => /andP[]. Qed.
imports: HB(structures) mathcomp(all_ssreflect) mathcomp(perm fingroup) tools combclass partition Yamanouchi ordtype std tableau