Computation of kernels for Algebra Homomorphisms of graded rings

[HechtiDerLachs]

The following code fails, probably due to a faulty translation between the Oscar and the Singular side:

R, (x,y,z) = QQ["x", "y", "z"]
R_ext, _ = PolynomialRing(R, ["u", "v", "w"])
S, (u,v,w) = grade(R_ext, [1,1,1])
f = AlgebraHomomorphism(S, S, [u*v^2, u*w^2, u*v*w])
K = kernel(f)

Interestingly, if one writes [u^2, v^2, w^2] in the map definition, it nevertheless outputs the correct kernel.

[thofma]

Yes, I think this is also #975 and #976 :-(

[fingolfin]

AlgebraHomomorphism is no more, but if I use hom this seems to work now?

julia> f = hom(S, S, [u*v^2, u*w^2, u*v*w])
Map with following data
Domain:
=======
S
Codomain:
=========
S

julia> kernel(f)
ideal(u*v - w^2)