English

Generating simple vigorous groups

Group Theory 2026-07-23 v1

Abstract

The simple vigorous groups form a broad class of groups of homeomorphisms of Cantor space that includes Thompson's group VV, its various generalisations and many others such as Nekrashevych's groups of dynamical origin. Bleak, Elliott and Hyde (2024) proved that every finitely generated simple vigorous group is 22-generated, and, in this paper, we give several strong generation results for this class of simple groups. For example, we prove that if GG is a finitely generated simple vigorous group, then GG is generated by three involutions, GG is generated by an element of order mm and an element of order nn for any choice of m2m \geq 2 and n3n \geq 3, GG has a minimal generating set of size kk for all k2k \geq 2, every nontrivial element of GG is contained in a generating pair and the direct power GnG^n is 22-generated for all nn. These results are analogous to well-known results for finite simple groups, but of course the proofs in this context are quite different. One consequence of our results is that Thompson's group VV is (2,3)(2, 3)-generated, which answers a question of Sapir (2017). Another consequence is that every finitely generated group quasi-isometrically embeds in a (2,3)(2, 3)-generated simple group, strengthening theorems of Hall (1974) and Bridson (1998). All of our proofs are constructive, and we establish several new generation criteria for these groups, which we expect to be of wider interest, even just for Thompson's group VV.

Cite

@article{arxiv.2607.21754,
  title  = {Generating simple vigorous groups},
  author = {Collin Bleak and Casey Donoven and Scott Harper and James Hyde},
  journal= {arXiv preprint arXiv:2607.21754},
  year   = {2026}
}

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25 pages