proposition: Lemma symp_homog d : sympol 'p_d \is d.-homog.
proof: Proof. Proof using. apply rpred_sum => m _. have /(dhomogMn d) : ('X_m : {mpoly R[n]}) \is 1.-homog. by rewrite dhomogX /= mdeg1. by rewrite mul1n. 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