English

Model-theoretic Tameness in finite extensions of groups

Logic 2026-05-15 v1 Group Theory

Abstract

It is shown that finite-index extensions and finite-index subgroups of ω\omega-stable groups can be model-theoretically wild. More precisely, there exists an ω\omega-stable group GG such that any given countable first-order structure in a finite language is interpretable both in some finite-index extension of GG and in some finite-index subgroup of GG.

Keywords

Cite

@article{arxiv.2605.14390,
  title  = {Model-theoretic Tameness in finite extensions of groups},
  author = {Yatir Halevi and Saharon Shelah},
  journal= {arXiv preprint arXiv:2605.14390},
  year   = {2026}
}