English

Veech groups of covers of the Chamanara surface

Geometric Topology 2025-10-23 v2

Abstract

We study finite abelian covers of the Chamanara surface, an example of a finite-area infinite translation surface with interesting dynamics and a large Veech group. Specifically, the Veech group of the Chamanara surface is a virtually free group on two generators. We characterize when finite abelian covers have large Veech groups themselves, namely when their Veech group has finite index in that of the Chamanara surface. For degree-2 covers, we provide a detailed analysis of these finite-index Veech groups. As an application, we prove that every free group arises as the projective Veech group of a finite-area infinite translation surface.

Keywords

Cite

@article{arxiv.2504.00956,
  title  = {Veech groups of covers of the Chamanara surface},
  author = {Mauro Artigiani and Anja Randecker and Chandrika Sadanand and Ferrán Valdez and Gabriela Weitze-Schmithüsen},
  journal= {arXiv preprint arXiv:2504.00956},
  year   = {2025}
}

Comments

v2: 40 pages, 7 figures, improved exposition and added more context; v1: 30 pages, 6 figures