Artinian implies IZ: Difference between revisions

From Commalg
(New page: ==Statement== ===Verbal statement=== Any Artinian ring is IZ: every element is either invertible, or a zero divisor. ==Proof== ''Given'': An Artinian ring <math>A</math...)
 
m (1 revision)
 
(No difference)

Latest revision as of 16:18, 12 May 2008

Statement

Verbal statement

Any Artinian ring is IZ: every element is either invertible, or a zero divisor.

Proof

Given: An Artinian ring A, and an element x∈A

To prove: x is invertible or a zero divisor

Proof: Consider the descending chain of ideals:

A⊃(x)⊃(x2)⊃…

By the Artinianness, this chain stabilizes at some point, so we have:

xn=axn+1

for some a∈A. Rewriting, we see that:

xn(1−ax)=0

If 1−ax=0, then x is invertible. Otherwise, xn is a zero divisor, and hence x is a zero divisor.