proposition: Fact is_homsym_submod_closed : submod_closed is_homsym.
proof: Proof. split => [|a p q Hp Hq]; rewrite !homsymE. - exact: dhomog0. - by apply rpredD => //; apply rpredZ. 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