Tiling the field $\mathbb{Q}_p$ of $p$-adic numbers by a function
Shilei Fan
TL;DR
This work analyzes tiling of the $p$-adic field $\mathbb{Q}_p$ by translations and establishes that any tiling function must be uniformly locally constant. It connects tiling by a set and by a function to uniform partitions of unity and to the Fuglede conjecture, proving a precise density relation for discrete tiling measures and providing a complete characterization of tiling structures in $\mathbb{Q}_p\times\mathbb{Z}/2\mathbb Z$ with spectrality results. The paper develops a robust $p$-adic harmonic-analytic framework using Bruhat-Schwartz distributions, Fourier analysis, and finite-group tiling theory to obtain both local and global tiling descriptions, including $p$-homogeneous tile structures and the spectral properties of tiles. Overall, it extends Fuglede-type tiling results to the infinite abelian group $\mathbb{Q}_p$ and an associated product, and it delivers detailed tile classifications across finite and $p$-adic settings that inform spectrality and partition structures in these groups.
Abstract
This study explores the properties of the function which can tile the field $\mathbb{Q}_p$ of $p$-adic numbers by translation. It is established that functions capable of tiling $\mathbb{Q}_p$ is by translation uniformly locally constancy. As an application, in the field $\mathbb{Q}_p$, we addressed the question posed by H. Leptin and D. Müller, providing the necessary and sufficient conditions for a discrete set to correspond to a uniform partition of unity. The study also connects these tiling properties to the Fuglede conjecture, which states that a measurable set is a tile if and only if it is spectral. The paper concludes by characterizing the structure of tiles in \(\mathbb{Q}_p \times \mathbb{Z}/2\mathbb{Z}\), proving that they are spectral sets.
