I'veI asked this question last year in MSE, but I didn't get anyan answer so I just want to post the question here, too.
I took a commutative algebra course last semester (withusing Kaplansky's book), and I'veI learned about Krull's intersection theorem. In the course, we proved it without using the Artin-Rees Lemma. I have heard that the standard proof uses the lemma.
By the way, isAre there any other simple or intuitive proofs for the theorem? I have heard that there is an intuitive reason for coordinate rings in this post post, that the only function which vanishes to arbitrarily high order at a point is the zero function. In case of polynomialpolynomials, this is easy to accept if we consider the polynomial as a Taylor series expansion (which ends in finitewith finitely many terms). With usingUsing this idea, I tried to prove it for a local ring :, as follows.
Let $R$ be a Noetherian ring. Suppose there exists $D:R\to R$ satisfiessatisfying $D(ab)=(Da)b+a(Db)$ and $D(a+b)=Da+Db$, i.e.that is, it works asis a derivation on $R$. Define $Poly(R):=\{r\in R\,| \,D^{k}r=0$$\mathrm {Poly}(R):=\{r\in R\,| \,D^{k}r=0$ for some $k>0\}$, which means that the set of elements in $R$ workson which $D$ behaves as a polynomial.
We can check that $Poly(R)$$\mathrm {Poly}(R)$ is a subring of $R$, and I wonder ifwhether $R=Poly(R)$ or not$R=\mathrm {Poly}(R)$. Then I want to approximate elements in $R$ as avia their Taylor expansion and I want to prove the theoremexpansions, but it was not easy to formalize itthis. I think that the evaluation map corresponds to quotients throughby maximal ideal of $R$,ideal; and then it would be possible to find a function $r^{*}:k\to k$ where $k=R/\mathfrak{m}$ is a field and $r^{*}$ is induced by an element $r\in R$.
All these things are possible in the case of polynomial ring, but it is very hard to do it for general Noetherian ringrings (or Noetherian local ringrings). I also noticed that there isn'taren't any nontrivial derivationderivations on a ringthe ring $\mathbb{Z}$$\mathbf{Z}$. Is there anya proof that uses these ideas? Or how can I modify these ideas or versions of them?