Let $S^1={\{ z \in \Bbb{C} : |z|=1 \}}$ be the unit circle.
Let $R= \mathcal{H}(S^1)$ be the ring of holomorphic functions on $S^1$, i.e. the ring of functions $f: S^1 \longrightarrow \Bbb{C}$ which can be extended to an holomorphic function on an open neighbourhood of $S^1$. My question is:
Is $R$ is a Noetherian ring?
What I tried:
We can think $R$ as a direct limit $$R= \lim_{\longrightarrow} \mathcal{H}(\Omega_n)$$ where $\Omega_n = \{ z \in \Bbb{C} : 1-\frac{1}{n} < |z| < 1+\frac{1}{n}\}$ denotes the open annulus of amplitude $2/n$ for $n\ge3$, and $$\mathcal{H}(\Omega_3) \longrightarrow \mathcal{H}(\Omega_4) \longrightarrow \mathcal{H}(\Omega_5) \longrightarrow \dots$$ is a direct system of rings whose maps are restrictions. Since restrictions are injective ring morphisms, we can think $R= \bigcup_n \mathcal{H}(\Omega_n)$
In particular $R$ is a Bezout domain (every finitely generated ideal of $R$ is principal). Now, if $R$ were Noetherian, then $R$ would be a PID.
And here I got stuck:
it could be possible that this is non-Noetherian since it is a union of non-Noetherian rings
on the other hand $S^1$ is compact, so every function $f \in R$ can only have a finite number of zeroes: this gives me intuition that maybe $R$ is a UFD.