English

Non-geometric veering triangulations

Geometric Topology 2014-06-26 v1

Abstract

Recently, Ian Agol introduced a class of "veering" ideal triangulations for mapping tori of pseudo-Anosov homeomorphisms of surfaces punctured along the singular points. These triangulations have very special combinatorial properties, and Agol asked if these are "geometric", i.e. realised in the complete hyperbolic metric with all tetrahedra positively oriented. This paper describes a computer program Veering, building on the program Trains by Toby Hall, for generating these triangulations starting from a description of the homeomorphism as a product of Dehn twists. Using this we obtain the first examples of non-geometric veering triangulations; the smallest example we have found is a triangulation with 13 tetrahedra.

Keywords

Cite

@article{arxiv.1406.6439,
  title  = {Non-geometric veering triangulations},
  author = {Craig D. Hodgson and Ahmad Issa and Henry Segerman},
  journal= {arXiv preprint arXiv:1406.6439},
  year   = {2014}
}
R2 v1 2026-06-22T04:46:28.668Z