English

Equationally separable classes of groups

Group Theory 2025-03-04 v2

Abstract

Over each nontrivial finite group GG, there exists a finite system of equations having no solutions in larger finite groups but having a solution in a periodic group containing GG. We prove several similar facts about amenable, orderable, locally indicable, solvable, nilpotent, and other classes of groups. As a byproduct, we also show that any amalgam of two countable periodic groups with finite intersection embeds into a periodic group, thereby answering a 1960 question of B. Neumann in the countable case.

Keywords

Cite

@article{arxiv.2502.05831,
  title  = {Equationally separable classes of groups},
  author = {Alexander Buturlakin and Anton Klyachko and Denis Osin},
  journal= {arXiv preprint arXiv:2502.05831},
  year   = {2025}
}

Comments

An inaccuracy in the proof of Theorem 5.1 (6) has been fixed

R2 v1 2026-06-28T21:37:39.348Z