English

Compact hyperbolic manifolds without spin structures

Geometric Topology 2021-01-06 v4 General Topology

Abstract

We exhibit the first examples of compact orientable hyperbolic manifolds that do not have any spin structure. We show that such manifolds exist in all dimensions n4n \geq 4. The core of the argument is the construction of a compact orientable hyperbolic 44-manifold MM that contains a surface SS of genus 33 with self intersection 11. The 44-manifold MM has an odd intersection form and is hence not spin. It is built by carefully assembling some right angled 120120-cells along a pattern inspired by the minimum trisection of CP2\mathbb{C}\mathbb{P}^2. The manifold MM is also the first example of a compact orientable hyperbolic 44-manifold satisfying any of these conditions: 1) H2(M,Z)H_2(M,\mathbb{Z}) is not generated by geodesically immersed surfaces. 2) There is a covering M~\tilde{M} that is a non-trivial bundle over a compact surface.

Keywords

Cite

@article{arxiv.1904.12720,
  title  = {Compact hyperbolic manifolds without spin structures},
  author = {Bruno Martelli and Stefano Riolo and Leone Slavich},
  journal= {arXiv preprint arXiv:1904.12720},
  year   = {2021}
}

Comments

23 pages, 16 figures

R2 v1 2026-06-23T08:52:21.530Z