English

Geodesics in the mapping class group

Group Theory 2021-12-01 v1 Geometric Topology

Abstract

We construct explicit examples of geodesics in the mapping class group and show that the shadow of a geodesic in mapping class group to the curve graph does not have to be a quasi-geodesic. We also show that the quasi-axis of a pseudo-Anosov element of the mapping class group may not have the strong contractibility property. Specifically, we show that, after choosing a generating set carefully, one can find a pseudo-Anosov homeomorphism f, a sequence of points w_k and a sequence of radii r_k so that the ball B(w_k, r_k) is disjoint from a quasi-axis a of f, but for any projection map from mapping class group to a, the diameter of the image of B(w_k, r_k) grows like log(r_k).

Keywords

Cite

@article{arxiv.1810.12489,
  title  = {Geodesics in the mapping class group},
  author = {Kasra Rafi and Yvon Verberne},
  journal= {arXiv preprint arXiv:1810.12489},
  year   = {2021}
}

Comments

16 pages, 3 figures

R2 v1 2026-06-23T04:57:01.143Z