proposition: Lemma syms1 (la : 'P_1) : 's[la] = \sum_(i < n) 'X_i :> {mpoly R[n]}.
proof: Proof. by rewrite /= Schur1. 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