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arXiv · 2410.20998

Spiders' webs in the Eremenko-Lyubich class

Lasse Rempe
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Abstract

Consider the entire function $f(z)=\cosh(z)$. We show that the escaping set of this function - that is, the set of points whose orbits tend to infinity under iteration - has a structure known as a "spider's web". This disproves a conjecture of Sixsmith from 2020. In fact, we show that the "fast escaping set", i.e. the set of points whose orbits tend to infinity at an iterated exponential rate, is a spider's web. This answers a question of Rippon and Stallard from 2012. We also discuss a wider class of functions to which our results apply, and state some open questions.

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Lasse Rempe. 2024-10-28. Spiders' webs in the Eremenko-Lyubich class. https://doi.org/10.1093/imrn%2Frnae278

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