English

Vertex-minimal hyperbolic origami 2-torus

Metric Geometry 2025-11-19 v2 Geometric Topology

Abstract

We show that there exists a geodesic triangulation TT of a hyperbolic genus 2 surface Σ2\Sigma_2 with 10 vertices and an isometric polyhedral embedding S:Σ2H3S: \Sigma_2 \hookrightarrow \mathbb{H}^3 that sends the triangles in TT to geodesic triangles in H3\mathbb{H}^3. We call this type of embedding a hyperbolic origami 2-torus. Since 10 is the combinatorially minimum number of vertices required to triangulate a genus 2 surface, this paper settles the question of minimum number of vertices required to obtain a hyperbolic origami 2-torus.

Keywords

Cite

@article{arxiv.2509.18668,
  title  = {Vertex-minimal hyperbolic origami 2-torus},
  author = {Zhengyu Zou},
  journal= {arXiv preprint arXiv:2509.18668},
  year   = {2025}
}

Comments

26 pages, 8 figures. This version includes a new result on 12-vertex 7-regular triangulations

R2 v1 2026-07-01T05:51:29.305Z