English

Pseudo-Anosovs are exponentially generic in mapping class groups

Geometric Topology 2024-07-24 v3 Group Theory

Abstract

Given a finite generating set SS, let us endow the mapping class group of a closed hyperbolic surface with the word metric for SS. We discuss the following question: does the proportion of non-pseudo-Anosov mapping classes in the ball of radius RR decrease to 0 as RR increases? We show that any finite subset SS' of the mapping class group is contained in a finite generating set SS such that this proportion decreases exponentially. Our strategy applies to weakly hyperbolic groups and does not refer to the automatic structure of the group.

Keywords

Cite

@article{arxiv.2110.06678,
  title  = {Pseudo-Anosovs are exponentially generic in mapping class groups},
  author = {Inhyeok Choi},
  journal= {arXiv preprint arXiv:2110.06678},
  year   = {2024}
}

Comments

Expanded the introduction and elaborated several details. 33 pages and 6 figures. The final version of this paper will appear in Geometry and Topology

R2 v1 2026-06-24T06:51:27.738Z