proposition: Lemma syms_symhM d1 (la : 'P_d1) d2 : 's[la] * 'h_d2 = \sum_(nu : 'P_(d1 + d2) | hb_strip la nu) 's[nu] :> SF.
proof: Proof. by apply val_inj; rewrite -syms_rowpartn /= Pieri_rowpartn raddf_sum. 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