Descend finiteness along quotients by nilpotent ideals #
theorem
Module.finite_of_surjective_of_ker_le_nilradical
{R : Type u_1}
{S : Type u_2}
{T : Type u_3}
[CommRing R]
[CommRing S]
[CommRing T]
[Algebra R S]
[Algebra R T]
[Module.Finite R T]
(f : S →ₐ[R] T)
(hf₁ : Function.Surjective ⇑f)
(hf₂ : RingHom.ker f ≤ nilradical S)
(hf₃ : (RingHom.ker f).FG)
:
Module.Finite R S
If I is a finitely generated nilpotent ideal of an R-algebra S, and T = S / I is
R-finite, then S is also R-finite.