2

$R$ is a commutative ring with $1$. Suppose every maximal ideal is finitely generated. Is this ring Noetherian? Equivalently, is every prime ideal finitely generated?

user26857
  • 52,094
user2902293
  • 2,659

1 Answers1

6

No.

A counterexample is the ring ${\cal O}(D)$ of the holomorphic functions defined on a domain $D\subset\Bbb C$. The maximal ideals are the ideals $\{(z-a){\cal O}(D)\}$ for $a\in D$ (which are principal), but there are ideals which are not finitely generated.

For instance, the ideal $I=\{\sin(nz)\}_{n\in\Bbb N}$ in ${\cal O}(\Bbb C)$ is proper (it is contained in $z{\cal O}(\Bbb C)$), but not finitely generated: look at the zero set of the elements in $I$.

AdLibitum
  • 3,003