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.
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.
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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.