proposition: Lemma symm_syms la : 'm[la] = \sum_(mu : 'P_d) 'K^-1(la, mu) *: 's[mu] :> SF.
proof: Proof. rewrite -(map_symm intr) symm_syms_int. rewrite rmorph_sum /=; apply eq_bigr => i _. by rewrite linearZ_LR /= map_syms. 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