English

On wreath product occurring as subgroup of automata group

Group Theory 2024-05-28 v1

Abstract

A finitely generated group is said to be an automata group if it admits a faithful self-similar finite-state representation on some regular mm-tree. We prove that if GG is a subgroup of an automata group, then for each finitely generated abelian group AA, the wreath product AGA \wr G is a subgroup of an automata group. We obtain, for example, that C2(C2Z)C_2 \wr (C_{2} \wr \mathbb{Z}), Z(C2Z)\mathbb{Z} \wr (C_2 \wr \mathbb{Z}), C2(ZZ)C_2 \wr (\mathbb{Z} \wr \mathbb{Z}), and Z(ZZ)\mathbb{Z} \wr (\mathbb{Z} \wr \mathbb{Z}) are subgroups of automata groups. In the particular case Z(ZZ)\mathbb{Z} \wr (\mathbb{Z} \wr \mathbb{Z}), we prove that it is a subgroup of a two-letters automata group; this solves Problem 15.19 - (b) of the Kourovka Notebook proposed by A. M. Brunner and S. Sidki in 2000 [8, 17].

Keywords

Cite

@article{arxiv.2405.16678,
  title  = {On wreath product occurring as subgroup of automata group},
  author = {Alex C. Dantas and Junio R. Oliveira and Tulio M. G. Santos},
  journal= {arXiv preprint arXiv:2405.16678},
  year   = {2024}
}