PreprintCC BY 4.0arXiv
Existence of a Hall ray in higher dimensional Lagrange spectra
Abstract
Given any norm |·|ℝ2 on ℝ2, we prove that the Lagrange spectrum for $2$-vectors contains a Hall ray. Equivalently, every sufficiently small ρ≥0 occurs as $\liminf_{q\to\infty}q^{1/2}\min_{p\in\mathbb Z^2}\|qx-p\|_{\mathbb R^2} $ for some x∈ℝ2∖ℚ2. Combined with a recent result of Kleinbock \cite{Kleinbock}, this implies that the $2$-dimensional Lagrange spectrum is either a ray, mirroring the behavior for Dirichlet spectra, or a ray preceded by a dense part.
Related
- An Introduction to the Lagrange and Markov Spectra through the Lens of Generalized Markov Numbers
- Distribution of points near the origin in the d-dimensional Lagrange spectrum
- Existence of Weak Solutions and Higher-Order Regularity for a Heat-Wave Fluid-Structure Interaction System on a Periodic Strip
- Normed idempotence of spectra and distributivity in equivariant higher algebra
- Existence of multi-dimensional pulsating fronts for KPP equations: a new formulation approach
BibTeX
@misc{cheung2026existence,
title = {{Existence of a Hall ray in higher dimensional Lagrange spectra}},
author = {Yitwah Cheung and Zhijing Wendy Wang and Ruichong Zhang},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.23464},
eprint = {2609.23464},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.23464},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Existence of a Hall ray in higher dimensional Lagrange spectra
AU - Yitwah Cheung
AU - Zhijing Wendy Wang
AU - Ruichong Zhang
PY - 2026
DA - 2026/09/20
PB - arXiv
DO - 10.48550/arxiv.2609.23464
UR - https://arxiv.org/abs/2609.23464
AB - Given any norm |·|_ℝ^2 on ℝ^2, we prove that the Lagrange spectrum for $2$-vectors contains a Hall ray. Equivalently, every sufficiently small ρ≥0 occurs as $\liminf_{q\to\infty}q^{1/2}\min_{p\in\mathbb Z^2}\|qx-p\|_{\mathbb R^2} $ for some x∈ℝ^2∖ℚ^2. Combined with a recent result of Kleinbock \cite{Kleinbock}, this implies that the $2$-dimensional Lagrange spectrum is either a ray, mirroring the behavior for Dirichlet spectra, or a ray preceded by a dense part.
ER -