Noetherian ring

1. Aug 17, 2008

peteryellow

prove that a commutative noetherian ring in which all primes are maximal is artinian.

2. Aug 17, 2008

morphism

So, what have you tried?

3. Aug 17, 2008

peteryellow

well I dont have an idea how to start...

4. Aug 17, 2008

peteryellow

Let there be given a decending chain of prime ideals I_1 \supset I_2 \supset I_3 \supset I_4 \supset.....

Since all primes are maximal therefore for a natural number n we have I_n =I_{n+1}. Hence the ring is artinian.

5. Aug 18, 2008

morphism

Why is it sufficient to look at descending chains of prime ideals? Is it true that if a ring R satisfies the descending chain condition on its prime ideals then R is Artinian? (No: take R=$\mathbb{Z}$.) Also, how did you conclude that I_n = I_{n+1}? This doesn't follow from maximality.

Try again!

[Side note: Incidentally, one can prove that every commutative Noetherian ring satisfies the descending chain condition on prime ideals. So if this were sufficient to determine if a ring is Artinian, then we would be able to conclude that every commutative Noetherian ring is Artinian, which is definitely not the case.]

Last edited: Aug 18, 2008