> M:=ModularSymbols(431);
> D:=NewformDecomposition(CuspidalSubspace(M));
> D:=SortDecomposition(D);
> E:=D[1];
> F:=D[2];
> qEigenform(E,11);
q - q^2 + q^3 - q^4 + q^5 - q^6 - 2*q^7 + 3*q^8 - 2*q^9 - q^10 + O(q^11)
> qEigenform(F,11);
q - q^2 + 3*q^3 - q^4 - 3*q^5 - 3*q^6 + 2*q^7 + 3*q^8 + 6*q^9 + 3*q^10 + O(q^11)
> qEigenform(E,11) - qEigenform(F,11);
-2*q^3 + 4*q^5 + 2*q^6 - 4*q^7 - 8*q^9 - 4*q^10 + O(q^11)
> IntersectionGroup(E,F);
Abelian Group of order 1