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arXiv 2006.02727math.GR
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一些不变生成群的例子

Some examples of invariably generated groups

Ashot Minasyan

摘要:

如果存在子集$S \subseteq G$,使得对于通过用共轭替换每个元素从$S$获得的每个子集$S' \subseteq G$,$S'$生成$G$,则不变地生成(IG)群$G$。另外,如果可以选择这样的子集$S$为有限的,则$G$是不可避免地生成的(图)。在本文中,我们构造了一个FIG群$G$,它具有一个索引$2$子群$N \lhd G$,使得$N$不是IG。这表明,无论是属性IG或FIG是稳定的下传递到子群的有限指数,回答问题的Wiegold和坎特,Lubotzky,Shalev。我们还产生了第一个例子,是不是FIG的,回答了考克斯的问题。

英文摘要:

A group $G$ is invariably generated (IG) if there is a subset $S \subseteq G$ such that for every subset $S' \subseteq G$, obtained from $S$ by replacing each element with a conjugate, $S'$ generates $G$. $G$ is finitely invariably generated (FIG) if, in addition, one can choose such a subset $S$ to be finite. In this note we construct a FIG group $G$ with an index $2$ subgroup $N \lhd G$ such that $N$ is not IG. This shows that neither property IG nor FIG is stable under passing to subgroups of finite index, answering questions of Wiegold and Kantor, Lubotzky, Shalev. We also produce the first examples of finitely generated IG groups that are not FIG, answering a question of Cox.

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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