arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2101.11291math.GR
收藏

哪些幂零群群是自相似的?

Which Nilpotent Groups are Self-Similar?

Olivier Mathieu

摘要:

设$Γ$是一个无挠生成的幂零群,$A^ω$是有限字母表$A$上的无限字空间.研究了$Γ$在$A^ω$上的两种自相似作用,即轨道稠密的忠实作用和自由作用.每种类型的自相似作用的存在性的标准建立。得到了关于零流形的两个推论。第一个涉及的nilmanifold赋予了Anosov同构,第二个关于仿射结构的存在。然后研究了$Γ$的虚作用,即有限指数子群$Γ'$的作用.一个公式,具有一定的数论内容,被发现的最小基数的字母表$A$赋予一个虚拟的自相似作用的$A^ω$的每一种类型。

英文摘要:

Let $Γ$ be a finitely generated torsion free nilpotent group, and let $A^ω$ be the space of infinite words over a finite alphabet $A$. We investigate two types of self-similar actions of $Γ$ on $A^ω$, namely the faithfull actions with dense orbits and the free actions. A criterion for the existence of a self-similar action of each type is established. Two corollaries about the nilmanifolds are deduced. The first involves the nilmanifolds endowed with an Anosov diffeomorphism, and the second about the existence of an affine structure. Then we investigate the virtual actions of $Γ$, i.e. actions of a subgroup $Γ'$ of finite index. A formula, with some number theoretical content, is found for the minimal cardinal of an alphabet $A$ endowed with a virtual self-similar action on $A^ω$ of each type.

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。

↑