On The Hausdorff Dimension of Weighted Badly Approximable Vectors

Fuente: arXiv
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Main Author: Lou, Yi
Format: Preprint
Published: 2026
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author Lou, Yi
author_facet Lou, Yi
contents Let $\boldsymbolτ=(τ_1,\dots,τ_m)\in \mathbb{R}_{\ge 0}^m$ satisfy $\sum_{i=1}^m τ_i>1$ and $τ_1\ge \cdots \ge τ_m$ Let $Ψ_{\boldsymbolτ}=(ψ_1,\dots,ψ_m)$ be given by $$ ψ_i(q)=q^{-τ_i}, \qquad i=1,\dots,m,$$ and denote by $\mathcal{A}_m(Ψ_{\boldsymbolτ})$ the set of $Ψ_{\boldsymbolτ}$-approximable vectors in $[0,1]^m$. The associated set of weighted $Ψ_{\boldsymbolτ}$-badly approximable vectors is defined by $$\mathcal{B}_m(Ψ_{\boldsymbolτ}) = \mathcal{A}_m(Ψ_{\boldsymbolτ}) \setminus \bigcap_{0<c<1}\mathcal{A}_m(cΨ_{\boldsymbolτ}).$$ The main result of this paper is that, for every ball $B\subseteq [0,1]^m$, \[ \dim_{\mathcal{H}}\bigl(B\cap \mathcal{B}_m(Ψ_{\boldsymbolτ})\bigr) = \dim_{\mathcal{H}}\mathcal{A}_m(Ψ_{\boldsymbolτ}). \] The proof extends the Cantor-type construction and mass distribution arguments of Koivusalo, Levesley, Ward, and Zhang from the unweighted to the weighted setting, and is independent of recent results on weighted exact approximation.
format Preprint
id arxiv_https___arxiv_org_abs_2603_06137
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle On The Hausdorff Dimension of Weighted Badly Approximable Vectors
Lou, Yi
Number Theory
11J13
Let $\boldsymbolτ=(τ_1,\dots,τ_m)\in \mathbb{R}_{\ge 0}^m$ satisfy $\sum_{i=1}^m τ_i>1$ and $τ_1\ge \cdots \ge τ_m$ Let $Ψ_{\boldsymbolτ}=(ψ_1,\dots,ψ_m)$ be given by $$ ψ_i(q)=q^{-τ_i}, \qquad i=1,\dots,m,$$ and denote by $\mathcal{A}_m(Ψ_{\boldsymbolτ})$ the set of $Ψ_{\boldsymbolτ}$-approximable vectors in $[0,1]^m$. The associated set of weighted $Ψ_{\boldsymbolτ}$-badly approximable vectors is defined by $$\mathcal{B}_m(Ψ_{\boldsymbolτ}) = \mathcal{A}_m(Ψ_{\boldsymbolτ}) \setminus \bigcap_{0<c<1}\mathcal{A}_m(cΨ_{\boldsymbolτ}).$$ The main result of this paper is that, for every ball $B\subseteq [0,1]^m$, \[ \dim_{\mathcal{H}}\bigl(B\cap \mathcal{B}_m(Ψ_{\boldsymbolτ})\bigr) = \dim_{\mathcal{H}}\mathcal{A}_m(Ψ_{\boldsymbolτ}). \] The proof extends the Cantor-type construction and mass distribution arguments of Koivusalo, Levesley, Ward, and Zhang from the unweighted to the weighted setting, and is independent of recent results on weighted exact approximation.
title On The Hausdorff Dimension of Weighted Badly Approximable Vectors
topic Number Theory
11J13
url https://arxiv.org/abs/2603.06137