proposition: Lemma homsymdotBr p q1 q2 : '[p | q1 - q2] = '[p | q1] - '[p | q2].
proof: Proof. by rewrite !(homsymdotC p) -rmorphB homsymdotBl. Qed.
imports: HB(structures) mathcomp(all_ssreflect) mathcomp(ssralg matrix vector ssrnum algC archimedean) mathcomp(fingroup perm) mathcomp(ssrcomplements freeg mpoly) tools sorted ordtype permuted partition permcent antisym Schur_mpoly Schur_altdef sympoly