English

Division rings for group algebras of virtually compact special groups and $3$-manifold groups

Group Theory 2025-02-21 v4

Abstract

Let kk be a division ring and let GG be either a torsion-free virtually compact special group or a finitely generated torsion-free 33-manifold group. We embed the group algebra kGkG in a division ring and prove that the embedding is Hughes-free whenever GG is locally indicable. In particular, we prove that Kaplansky's Zero Divisor Conjecture holds for all group algebras of torsion-free 33-manifold groups. The embedding is also used to confirm a conjecture of Kielak and Linton. Thanks to the work of Jaikin-Zapirain and Linton, another consequence of the embedding is that kGkG is coherent whenever GG is a virtually compact special one-relator group. If GG is a torsion-free one-relator group, let kG\overline{kG} be the division ring containing kGkG constructed by Lewin and Lewin. We prove that kG\overline{kG} is Hughes-free whenever a Hughes-free kGkG-division ring exists. This is always the case when kk is of characteristic zero; in positive characteristic, our previous result implies that this happens when GG is virtually compact special.

Keywords

Cite

@article{arxiv.2303.08165,
  title  = {Division rings for group algebras of virtually compact special groups and $3$-manifold groups},
  author = {Sam P. Fisher and Pablo Sánchez-Peralta},
  journal= {arXiv preprint arXiv:2303.08165},
  year   = {2025}
}

Comments

32 pages. Corrected title