Non-uniqueness of characteristic curves of folding rational maps
Abstract
A folding rational map is a postcritically finite rational map f admitting an essential Jordan curve β, disjoint from the postcritical set Pf, whose preimage is disconnected and consists of Jordan curves homotopic to β relative to Pf. Such β is called a characteristic curve of f. We construct a real postcritically finite rational map f of degree $6$ with #Pf=4, which admits two non-homotopic characteristic curves β and β'. It is hyperbolic with orbifold signature (2,2,3,∞). This non-uniqueness is not a Lattès phenomenon, nor does it arise from a mating decomposition. The map is constructed piecewise, and a numerical model is provided to illustrate its dynamics. Thurston obstructions are excluded by arc-lifting and intersection-number arguments.
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BibTeX
@misc{yang2026nonuniqueness,
title = {{Non-uniqueness of characteristic curves of folding rational maps}},
author = {Luxian Yang and Jinsong Zeng},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.16576},
eprint = {2609.16576},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.16576},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Non-uniqueness of characteristic curves of folding rational maps
AU - Luxian Yang
AU - Jinsong Zeng
PY - 2026
DA - 2026/09/15
PB - arXiv
DO - 10.48550/arxiv.2609.16576
UR - https://arxiv.org/abs/2609.16576
AB - A folding rational map is a postcritically finite rational map f admitting an essential Jordan curve β, disjoint from the postcritical set P_f, whose preimage is disconnected and consists of Jordan curves homotopic to β relative to P_f. Such β is called a characteristic curve of f. We construct a real postcritically finite rational map f of degree $6$ with #P_f=4, which admits two non-homotopic characteristic curves β and β'. It is hyperbolic with orbifold signature (2,2,3,∞). This non-uniqueness is not a Lattès phenomenon, nor does it arise from a mating decomposition. The map is constructed piecewise, and a numerical model is provided to illustrate its dynamics. Thurston obstructions are excluded by arc-lifting and intersection-number arguments.
ER -