共度 HNN 扩张：非正曲率与双自动性
群论
2021-07-21 v4
摘要
我们证明了双自动群中任意拟凸阿贝尔子群的共度子在抽象共度子中具有有限像，即它是小的。利用这一判据，我们给出了是 CAT(0) 但不是双自动的群。这些群还解决了若干其他关于 CAT(0) 群的问题。
引用
@article{arxiv.1907.03515,
title = {Commensurating HNN-extensions: non-positive curvature and biautomaticity},
author = {Ian J. Leary and Ashot Minasyan},
journal= {arXiv preprint arXiv:1907.03515},
year = {2021}
}
备注
v4: 41 pages, re-formatted in G&T style. Some misprints have been corrected and references to recent results by other authors have been added