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arXiv 0905.1624math.GR
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有限指数子群与恰无穷性质

Subgroups of finite index and the just infinite property

Colin Reid

摘要:

一个剩余有限(profinite)群$G$是恰好无限的,如果$G$的每个非平凡(闭)正规子群是有限指数的。本文考虑了判定一个正无限群的(闭)子群$H$自身是否正无限的问题.若$G$不是虚交换的,则给出正规子群的恰无穷性的一个用极大子群表示的刻划.特别地,我们证明了这样的群$G$是遗传的恰好无限的当且仅当所有有限指数的极大子群恰好无限。我们还获得了某些家庭的虚拟阿贝尔群,包括所有的虚拟阿贝尔亲$p$集团和他们的离散类似物的结果。

英文摘要:

A residually finite (profinite) group $G$ is just infinite if every non-trivial (closed) normal subgroup of $G$ is of finite index. This paper considers the problem of determining whether a (closed) subgroup $H$ of a just infinite group is itself just infinite. If $G$ is not virtually abelian, we give a description of the just infinite property for normal subgroups in terms of maximal subgroups. In particular, we show that such a group $G$ is hereditarily just infinite if and only if all maximal subgroups of finite index are just infinite. We also obtain results for certain families of virtually abelian groups, including all virtually abelian pro-$p$ groups and their discrete analogues.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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