Hausdorff dimension estimates for Sudler products with positive lower bound

Fuente: arXiv
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Main Authors: Gayfulin, Dmitry, Hauke, Manuel
Format: Preprint
Published: 2023
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author Gayfulin, Dmitry
Hauke, Manuel
author_facet Gayfulin, Dmitry
Hauke, Manuel
contents Given an irrational number $α$, we study the asymptotic behaviour of the Sudler product denoted by $P_N(α) = \prod_{r=1}^N 2\lvert \sin πr α\rvert$. We show that $\liminf_{N \to \infty} P_N(α) >0$ and $\limsup_{N \to \infty} P_N(α)/N < \infty$ whenever the sequence of partial quotients in the continued fraction expansion of $α$ exceeds 3 only finitely often, which confirms a conjecture of the second-named author and partially answers a question of J. Shallit. Furthermore, we show that the Hausdorff dimension of the set of those $α$ that satisfy $\limsup_{N \to \infty} P_N(α)/N < \infty,\liminf_{N \to \infty} P_N(α) >0$ lies between $0.7056$ and $0.8677$, which makes significant progress in a question raised by Aistleitner, Technau, and Zafeiropoulos. We also show that the set of such $α$ is invariant under the Gauss map $T$.
format Preprint
id arxiv_https___arxiv_org_abs_2312_06548
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Hausdorff dimension estimates for Sudler products with positive lower bound
Gayfulin, Dmitry
Hauke, Manuel
Number Theory
11J70, 26D05
Given an irrational number $α$, we study the asymptotic behaviour of the Sudler product denoted by $P_N(α) = \prod_{r=1}^N 2\lvert \sin πr α\rvert$. We show that $\liminf_{N \to \infty} P_N(α) >0$ and $\limsup_{N \to \infty} P_N(α)/N < \infty$ whenever the sequence of partial quotients in the continued fraction expansion of $α$ exceeds 3 only finitely often, which confirms a conjecture of the second-named author and partially answers a question of J. Shallit. Furthermore, we show that the Hausdorff dimension of the set of those $α$ that satisfy $\limsup_{N \to \infty} P_N(α)/N < \infty,\liminf_{N \to \infty} P_N(α) >0$ lies between $0.7056$ and $0.8677$, which makes significant progress in a question raised by Aistleitner, Technau, and Zafeiropoulos. We also show that the set of such $α$ is invariant under the Gauss map $T$.
title Hausdorff dimension estimates for Sudler products with positive lower bound
topic Number Theory
11J70, 26D05
url https://arxiv.org/abs/2312.06548