English

The Teichm\"uller distance between finite index subgroups of $PSL_2(\mathbb{Z})$

Complex Variables 2007-07-04 v1 Geometric Topology

Abstract

For a given ϵ>0\epsilon >0, we show that there exist two finite index subgroups of PSL2(Z)PSL_2(\mathbb{Z}) which are (1+ϵ)(1+\epsilon)-quasisymmetrically conjugated and the conjugation homeomorphism is not conformal. This implies that for any ϵ>0\epsilon>0 there are two finite regular covers of the Modular once punctured torus T0T_0 (or just the Modular torus) and a (1+ϵ)(1+\epsilon)-quasiconformal between them that is not homotopic to a conformal map. As an application of the above results, we show that the orbit of the basepoint in the Teichm\"uller space T(§)T(\S) of the punctured solenoid §\S under the action of the corresponding Modular group (which is the mapping class group of §\S \cite{NS}, \cite{Odd}) has the closure in T(§)T(\S) strictly larger than the orbit and that the closure is necessarily uncountable.

Keywords

Cite

@article{arxiv.0707.0308,
  title  = {The Teichm\"uller distance between finite index subgroups of $PSL_2(\mathbb{Z})$},
  author = {Vladimir Markovic and Dragomir Saric},
  journal= {arXiv preprint arXiv:0707.0308},
  year   = {2007}
}

Comments

23 pages, 5 Figures