Phragmén-Lindelöf Principles and Julia Limiting Directions of Quasiregular Mappings

Fuente: arXiv
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Main Authors: Fletcher, Alastair N., Steranka, Julie M.
Format: Preprint
Published: 2023
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author Fletcher, Alastair N.
Steranka, Julie M.
author_facet Fletcher, Alastair N.
Steranka, Julie M.
contents We show that the set of Julia limiting directions of a transcendental-type $K$-quasiregular mapping $f:\mathbb{R}^n\to \mathbb{R}^n$ must contain a component of a certain size, depending on the dimension $n$, the maximal dilatation $K$, and the order of growth of $f$. In particular, we show that if the order of growth is small enough, then every direction is a Julia limiting direction. We also show that if every component of the set of Julia limiting directions is a point, then $f$ has infinite order. The main tool in proving these results is a new version of a Phragmén-Lindelöf principle for sub-$F$-extremals in sectors, where we allow for boundary growth of the form $O( \log |x| )$ instead of the previously considered $O(1)$ bound.
format Preprint
id arxiv_https___arxiv_org_abs_2303_17053
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Phragmén-Lindelöf Principles and Julia Limiting Directions of Quasiregular Mappings
Fletcher, Alastair N.
Steranka, Julie M.
Dynamical Systems
Complex Variables
37F31 (Primary) 30C65, 31C45 (Secondary)
We show that the set of Julia limiting directions of a transcendental-type $K$-quasiregular mapping $f:\mathbb{R}^n\to \mathbb{R}^n$ must contain a component of a certain size, depending on the dimension $n$, the maximal dilatation $K$, and the order of growth of $f$. In particular, we show that if the order of growth is small enough, then every direction is a Julia limiting direction. We also show that if every component of the set of Julia limiting directions is a point, then $f$ has infinite order. The main tool in proving these results is a new version of a Phragmén-Lindelöf principle for sub-$F$-extremals in sectors, where we allow for boundary growth of the form $O( \log |x| )$ instead of the previously considered $O(1)$ bound.
title Phragmén-Lindelöf Principles and Julia Limiting Directions of Quasiregular Mappings
topic Dynamical Systems
Complex Variables
37F31 (Primary) 30C65, 31C45 (Secondary)
url https://arxiv.org/abs/2303.17053