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

Eusebio Gardella; Owen Tanner

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arXiv · 2302.04078

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

Eusebio Gardella·Owen Tanner

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Abstract

We study a class of generalisations of Thompson's group $V$ 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 $V$, 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.

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Eusebio Gardella, Owen Tanner. 2023-02-08. Generalisations of Thompson's group V arising from purely infinite groupoids. https://arxiv.org/abs/2302.04078

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