proposition: Lemma sympolyf_evalX (i : 'I_m) : sympolyf_eval 'X_i = 'e_i.+1.
proof: Proof. by apply val_inj; rewrite /= -sympolyf_evalE comp_mpolyXU nth_mktuple. 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