English

Free $\mathbb Q$-groups are residually torsion-free nilpotent

Group Theory 2026-02-05 v3 Rings and Algebras

Abstract

We develop a method to show that some (abstract) groups can be embedded into a free pro-pp group. In particular, we show that a finitely generated subgroup of a free Q\mathbb Q-group can be embedded into a free pro-pp group for almost all primes pp. This solves an old problem raised by G. Baumslag: free Q\mathbb Q-groups are residually torsion-free nilpotent.

Keywords

Cite

@article{arxiv.2212.00402,
  title  = {Free $\mathbb Q$-groups are residually torsion-free nilpotent},
  author = {Andrei Jaikin-Zapirain},
  journal= {arXiv preprint arXiv:2212.00402},
  year   = {2026}
}

Comments

A mistake in the proof of Theorem 5.8 is corrected

R2 v1 2026-06-28T07:19:15.203Z