Question about proof of Krull principal ideal theorem

77 Views Asked by At

How can we explain the following step in the proof of Krull principal ideal theorem: $l\{ ((z):x^n)/(z) \}$ or $l\{ ((x^n):z)/(x^n) \}$ is finite?

$l(M)$ - length of module.

1

There are 1 best solutions below

2
On BEST ANSWER

If $I\subset R$ is an $M$-primary ideal then $R/I$ is artinian. In particular, every ideal $J/I$ if $R/I$ is an $R/I$-module of finite length, hence an $R$-module of finite length.