English

Categoricity and non-arithmetic Fuchsian groups

Logic 2026-02-13 v1

Abstract

Let ΓPSL2(R)\Gamma \subset PSL_2(\mathbb{R}) be a non-arithmetic Fuchsian group of the first kind with finite covolume, and let jΓj_{\Gamma} be a corresponding uniformizer. In this paper we introduce a natural Lω1,ωL_{\omega_1,\omega}-axiomatization TSFT^{\infty}_{SF} of the theory of jΓj_{\Gamma} viewed as a covering map. We show that TSFT^{\infty}_{SF} is categorical in all infinite cardinalities, extending to the non-arithmetic setting earlier results of Daw and Harris obtained in the arithmetic case. We also show that the associated first-order theory TjΓT_{j_{\Gamma}} is complete, admits elimination of quantifiers, and is ω\omega-stable.

Keywords

Cite

@article{arxiv.2602.11432,
  title  = {Categoricity and non-arithmetic Fuchsian groups},
  author = {John Baldwin and Joel Nagloo},
  journal= {arXiv preprint arXiv:2602.11432},
  year   = {2026}
}
R2 v1 2026-07-01T10:32:48.707Z