English

Train track complex of once-punctured torus and 4-punctured sphere

General Topology 2009-01-08 v1 Algebraic Geometry

Abstract

Consider a compact oriented surface SS of genus g0g \geq 0 and m0m \geq 0 punctured. The train track complex of SS which is defined by Hamenst\"adt is a 1-complex whose vertices are isotopy classes of complete train tracks on SS. Hamenst\"adt shows that if 3g3+m23g-3+m \geq 2, the mapping class group acts properly discontinuously and cocompactly on the train track complex. We will prove corresponding results for the excluded case, namely when SS is a once-punctured torus or a 4-punctured sphere. To work this out, we redefinition of two complexes for these surfaces.

Keywords

Cite

@article{arxiv.0901.0747,
  title  = {Train track complex of once-punctured torus and 4-punctured sphere},
  author = {Keita Ibaraki},
  journal= {arXiv preprint arXiv:0901.0747},
  year   = {2009}
}

Comments

19 pages, 13 figures

R2 v1 2026-06-21T11:58:07.762Z