English

Generalisations of Thompson's group V arising from purely infinite groupoids

Group Theory 2024-04-29 v2 Dynamical Systems Operator Algebras

Abstract

We study a class of generalisations of Thompson's group VV arising naturally as topological full groups of purely infinite, minimal groupoids. In the process, we show that the derived subgroup of such a group is 2-generated whenever it is finitely generated and has no proper characters in full generality. We characterise this class of groupoids through a number of group-theoretic conditions on their full groups including vigor, the existence of suitable embeddings of VV, and compressibility. We moreover give a complete abstract characterisation of those groups that arise as either topological full groups or derived subgroups of purely infinite, minimal groupoids. As an application, we describe all proper characters of the Brin-Higman-Thompson groups.

Keywords

Cite

@article{arxiv.2302.04078,
  title  = {Generalisations of Thompson's group V arising from purely infinite groupoids},
  author = {Eusebio Gardella and Owen Tanner},
  journal= {arXiv preprint arXiv:2302.04078},
  year   = {2024}
}

Comments

25 pages. v2: One of the conditions in Theorem A was removed, since it is not equivalent to the remaining ones. Otherwise only minor changes