The Brjuno and Wilton Functions

Fuente: arXiv
Enregistré dans:
Détails bibliographiques
Auteurs principaux: Burrin, Claire, Lee, Seul Bee, Marmi, Stefano
Format: Preprint
Publié: 2025
Sujets:
Accès en ligne:
Tags: Ajouter un tag
Pas de tags, Soyez le premier à ajouter un tag!
_version_ 1866910869802188800
author Burrin, Claire
Lee, Seul Bee
Marmi, Stefano
author_facet Burrin, Claire
Lee, Seul Bee
Marmi, Stefano
contents The Brjuno and Wilton functions bear a striking resemblance, despite their very different origins; while the Brjuno function $B(x)$ is a fundamental tool in one-dimensional holomorphic dynamics, the Wilton function $W(x)$ stems from the study of divisor sums and self-correlation functions in analytic number theory. We show that these perspectives are unified by the semi-Brjuno function $B_0(x)$. Namely, $B(x)$ and $W(x)$ can be expressed in terms of the even and odd parts of $B_0(x)$, respectively, up to a bounded defect. Based on numerical observations, we further analyze the arising functions $Δ^+(x) = B^+(x) - 2B_0^+(x)$ and $Δ^-(x) = W^-(x) - 2B_0^-(x)$, the first of which is Hölder continuous whereas the second exhibits discontinuities at rationals, behaving similarly to the classical popcorn function.
format Preprint
id arxiv_https___arxiv_org_abs_2503_08206
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The Brjuno and Wilton Functions
Burrin, Claire
Lee, Seul Bee
Marmi, Stefano
Dynamical Systems
37F50, 11J70
The Brjuno and Wilton functions bear a striking resemblance, despite their very different origins; while the Brjuno function $B(x)$ is a fundamental tool in one-dimensional holomorphic dynamics, the Wilton function $W(x)$ stems from the study of divisor sums and self-correlation functions in analytic number theory. We show that these perspectives are unified by the semi-Brjuno function $B_0(x)$. Namely, $B(x)$ and $W(x)$ can be expressed in terms of the even and odd parts of $B_0(x)$, respectively, up to a bounded defect. Based on numerical observations, we further analyze the arising functions $Δ^+(x) = B^+(x) - 2B_0^+(x)$ and $Δ^-(x) = W^-(x) - 2B_0^-(x)$, the first of which is Hölder continuous whereas the second exhibits discontinuities at rationals, behaving similarly to the classical popcorn function.
title The Brjuno and Wilton Functions
topic Dynamical Systems
37F50, 11J70
url https://arxiv.org/abs/2503.08206