English

The pants graph as a combinatorial model for the Teichmüller space of a non-orientable surface

Geometric Topology 2026-07-17 v1

Abstract

We study the relation between the pants graph of a non-orientable surface and that of its orientable double cover. Given a non-orientable surface NN with orientable double cover π ⁣:SN\pi\colon S\to N, we construct a natural map between pants graphs induced by lifting pants decompositions. We prove that this map defines a quasi-isometric embedding of Pants(N)\mathrm{Pants}(N) into Pants(S)\mathrm{Pants}(S). Using Brock's quasi-isometry between Pants(S)\mathrm{Pants}(S) and Teichm\"uller space Teich(S)\mathrm{Teich}(S) endowed with the Weil-Petersson metric, together with the identification of the Teichm\"uller space of NN with the fixed-point locus of the deck involution on Teich(S)\mathrm{Teich}(S), we prove that Pants(N)\mathrm{Pants}(N) is quasi-isometric to the Teichm\"uller space of NN equipped with the induced Weil-Petersson metric.

Keywords

Cite

@article{arxiv.2607.15792,
  title  = {The pants graph as a combinatorial model for the Teichmüller space of a non-orientable surface},
  author = {Michał Stukow and Błażej Szepietowski and Jakub Szmelter-Tomczuk},
  journal= {arXiv preprint arXiv:2607.15792},
  year   = {2026}
}