English

On McMullen-like mappings

Dynamical Systems 2014-03-12 v1

Abstract

We introduce a generalization of the McMullen family fλ(z)=zn+λ/zdf_{\lambda}(z)=z^n+\lambda/z^d. In 1988, C. McMullen showed that the Julia set of fλf_{\lambda} is a Cantor set of circles if and only if 1/n+1/d<11/n+1/d<1 and the simple critical values of fλf_{\lambda} belong to the trap door. We generalize this behavior defining a McMullen-like mapping as a rational map ff associated to a hyperbolic postcritically finite polynomial PP and a pole data D\mathcal{D} where we encode, basically, the location of every pole of ff and the local degree at each pole. In the McMullen family, the polynomial PP is zznz\mapsto z^n and the pole data D\mathcal{D} is the pole located at the origin that maps to infinity with local degree dd. As in the McMullen family fλf_{\lambda}, we can characterize a McMullen-like mapping using an arithmetic condition depending only on the polynomial PP and the pole data D\mathcal{D}. We prove that the arithmetic condition is necessary using the theory of Thurston's obstructions, and sufficient by quasiconformal surgery.

Keywords

Cite

@article{arxiv.1403.2420,
  title  = {On McMullen-like mappings},
  author = {Antonio Garijo and Sébastien Godillon},
  journal= {arXiv preprint arXiv:1403.2420},
  year   = {2014}
}

Comments

21 pages, 2 figures

R2 v1 2026-06-22T03:23:56.375Z