proposition: Lemma syme1 : val ('e_1) = \sum_(i < n) 'X_i.
proof: Proof. Proof using. by rewrite /= mesym1E. Qed.
imports: HB(structures) mathcomp(all_ssreflect) mathcomp(ssralg ssrint fingroup perm) mathcomp(ssrcomplements freeg mpoly) sorted tools ordtype permuted partition skewpart composition Yamanouchi std tableau stdtab skewtab permcent antisym Schur_mpoly therule Schur_altdef unitriginv