On a theorem by Brewer

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• 作者：Le Thi Ngoc Giau ^{ngocgiau@postech.ac.kr" class="auth_mail" title="E-mail the corresponding author} ; Byung Gyun Kang ; ^{bgkang@postech.ac.kr" class="auth_mail" title="E-mail the corresponding author}
• 关键词：13A15 ; 13C15 ; 13F25
• 刊名：Journal of Pure and Applied Algebra
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：221
• 期：1
• 页码：36-44
• 全文大小：318 K

文摘

One of the most frequently referenced monographs on power series rings, “Power Series over Commutative Rings” by James W. Brewer, states in Theorem 21 that if M is a non-SFT maximal ideal of a commutative ring R   with identity, then there exists an infinite ascending chain of prime ideals in the power series ring 46c45e341f4" title="Click to view the MathML source">R〚X〛$R〚X〛$, 6b157957629b804a1063e4f7" title="Click to view the MathML source">Q₀⊊Q₁⊊⋯⊊Q_n⊊⋯$Q_0⊊Q_1⊊\cdots ⊊Q_n⊊\cdots$ such that Q_n∩R=M$Q_n\cap R=M$ for each n  . Moreover, the height of M〚X〛$M〚X〛$ is infinite. In this paper, we show that the above theorem is false by presenting two counter examples. The first counter example shows that the height of M〚X〛$M〚X〛$ can be zero (and hence there is no chain 6b157957629b804a1063e4f7" title="Click to view the MathML source">Q₀⊊Q₁⊊⋯⊊Q_n⊊⋯$Q_0⊊Q_1⊊\cdots ⊊Q_n⊊\cdots$ of prime ideals in 46c45e341f4" title="Click to view the MathML source">R〚X〛$R〚X〛$ satisfying Q_n∩R=M$Q_n\cap R=M$ for each n). In this example, the ring R   is one-dimensional. In the second counter example, we prove that even if the height of M〚X〛$M〚X〛$ is uncountably infinite, there may be no infinite chain {Q_n}$\{Q_n\}$ of prime ideals in 46c45e341f4" title="Click to view the MathML source">R〚X〛$R〚X〛$ satisfying Q_n∩R=M$Q_n\cap R=M$ for each n.