English

Comparing Teichm\"uller and curve graph translation lengths

Geometric Topology 2025-08-01 v3

Abstract

A pseudo-Anosov mapping class acts on Teichm\"uller space T\mathcal{T} as well as on the curve graph C\mathcal{C} with so called north-south dynamics. We can measure a stable translation length lTl_\mathcal{T} and lCl_\mathcal{C} of the respective actions. Boissy and Lanneau compute the minimal Teichm\"uller translation length over all pseudo Anosovs in a fixed genus that lie in a hyperelliptic component of translation surfaces. In particular, this minimum is always greater than log(2),\log(\sqrt{2}), independently of the genus. Here, we show that the minimal stable curve graph translation length over the same family of pseudo-Anosovs behaves differently: Namely, for a genus gg surface this minimal translation length is of order 1g.\frac{1}{g}. To prove this result, we combine techniques that are used to find upper and lower bounds for the stable curve graph translation length with the Rauzy-Veech induction machinery. We proceed with showing that for a fixed genus gg there is a sequence of pseudo-Anosovs fnf_n with limnlT(fn)= and lC(fn)1g1\lim\limits_{n \to \infty} l_\mathcal{T}(f_n) = \infty \text{ and } l_\mathcal{C}(f_n) \le \frac{1}{g-1} for all nN.n \in \mathbb{N}. As a corollary, we obtain that there are stable curve graph translation lengths with infinite multiplicity, i.e. there exists qQq \in \mathbb{Q} and infinitely many, non-conjugate pseudo-Anosovs fnf_n with lC(fn)=ql_\mathcal{C}(f_n) = q for all n.n.

Keywords

Cite

@article{arxiv.2501.16563,
  title  = {Comparing Teichm\"uller and curve graph translation lengths},
  author = {Philipp Bader},
  journal= {arXiv preprint arXiv:2501.16563},
  year   = {2025}
}
R2 v1 2026-06-28T21:20:57.235Z