Commensurating HNN extensions: nonpositive curvature and biautomaticity

IF 2 1区数学 Geometry & Topology Pub Date : 2019-07-08 DOI:10.2140/gt.2021.25.1819

I. Leary, A. Minasyan

引用次数: 27

Abstract

We show that the commensurator of any quasiconvex abelian subgroup in a biautomatic group is small, in the sense that it has finite image in the abstract commensurator of the subgroup. Using this criterion we exhibit groups that are CAT(0) but not biautomatic. These groups also resolve a number of other questions concerning CAT(0) groups.

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通约HNN扩展:非正曲率和双自动性

证明了双自动群中任意拟凸阿贝尔子群的通约数都是小的，即它在子群的抽象通约数上有有限象。使用这个标准，我们展示了CAT(0)但不是双自动的组。这些组还解决了一些关于CAT(0)组的其他问题。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Geometry & Topology 数学-数学

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5.00%

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期刊介绍： Geometry and Topology is a fully refereed journal covering all of geometry and topology, broadly understood. G&T is published in electronic and print formats by Mathematical Sciences Publishers. The purpose of Geometry & Topology is the advancement of mathematics. Editors evaluate submitted papers strictly on the basis of scientific merit, without regard to authors" nationality, country of residence, institutional affiliation, sex, ethnic origin, or political views.

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