proposition: Lemma symm_oversize sh : n < size sh -> 'm[sh] = 0.
proof: Proof. by rewrite ltnNge /symm => /negbTE ->. 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