English

Accessibility and Twin-width

Group Theory 2026-07-07 v1 Combinatorics

Abstract

We show that finite twin-width does not imply accessibility for finitely generated groups, which answers a question of Esperet. That is, we prove that there exists a finitely generated group Γ\Gamma that has finite uniform twin-width but is not accessible. In particular, for every finite generating set SS of Γ\Gamma, the Cayley graph Cay(Γ;S)Cay(\Gamma ; S) has finite twin-width but is not accessible. The example is obtained by combining Wilkes construction of a finitely generated inaccessible residually pp-finite groups with a result of Bonnet, Geniet, Tessera and Thomasse regarding the twin-width of groups acting faithfully on regular rooted trees.

Cite

@article{arxiv.2607.05713,
  title  = {Accessibility and Twin-width},
  author = {George Kontogeorgiou and Bobby Miraftab},
  journal= {arXiv preprint arXiv:2607.05713},
  year   = {2026}
}

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8 pages