Fugledes conjecture in $mathbb{Q}_p$ is proved. That is to say, a Borel set of positive and finite Haar measure in $mathbb{Q}_p$ is a spectral set if and only if it tiles $mathbb{Q}_p$ by translation.
In this article, we prove that a compact open set in the field $mathbb{Q}_p$ of $p$-adic numbers is a spectral set if and only if it tiles $mathbb{Q}_p$ by translation, and also if and only if it is $p$-homogeneous which is easy to check. We also cha
racterize spectral sets in $mathbb{Z}/p^n mathbb{Z}$ ($pge 2$ prime, $nge 1$ integer) by tiling property and also by homogeneity. Moreover, we construct a class of singular spectral measures in $mathbb{Q}_p$, some of which are self-similar measures.
Let $mu$ be a nonnegative Borel measure on the open unit disk $mathbb{D}subsetmathbb{C}$. This note shows how to decide that the Mobius invariant space $mathcal{Q}_p$, covering $mathcal{BMOA}$ and $mathcal{B}$, is boundedly (resp., compactly) embedde
d in the quadratic tent-type space $T^infty_p(mu)$. Interestingly, the embedding result can be used to determine the boundedness (resp., the compactness) of the Volterra-type and multiplication operators on $mathcal{Q}_p$.
Any bounded tile of the field $mathbb{Q}_p$ of $p$-adic numbers is a compact open set up to a zero Haar measure set. In this note, we give a simple and direct proof of this fact.
We study the Chabauty compactification of two families of closed subgroups of $SL(n,mathbb{Q}_p)$. The first family is the set of all parahoric subgroups of $SL(n,mathbb{Q}_p)$. Although the Chabauty compactification of parahoric subgroups is well st
udied, we give a different and more geometric proof using various Levi decompositions of $SL(n,mathbb{Q}_p)$. Let $C$ be the subgroup of diagonal matrices in $SL(n, mathbb{Q}_p)$. The second family is the set of all $SL(n,mathbb{Q}_p)$-conjugates of $C$. We give a classification of the Chabauty limits of conjugates of $C$ using the action of $SL(n,mathbb{Q}_p)$ on its associated Bruhat--Tits building and compute all of the limits for $nleq 4$ (up to conjugacy). In contrast, for $ngeq 7$ we prove there are infinitely many $SL(n,mathbb{Q}_p)$-nonconjugate Chabauty limits of conjugates of $C$. Along the way we construct an explicit homeomorphism between the Chabauty compactification in $mathfrak{sl}(n, mathbb{Q}_p)$ of $SL(n,mathbb{Q}_p)$-conjugates of the $p$-adic Lie algebra of $C$ and the Chabauty compactification of $SL(n,mathbb{Q}_p)$-conjugates of $C$.
Let $p(cdot): mathbb R^nto(0,infty)$ be a variable exponent function satisfying the globally log-Holder continuous condition. In this article, the authors first obtain a decomposition for any distribution of the variable weak Hardy space into good an
d bad parts and then prove the following real interpolation theorem between the variable Hardy space $H^{p(cdot)}(mathbb R^n)$ and the space $L^{infty}(mathbb R^n)$: begin{equation*} (H^{p(cdot)}(mathbb R^n),L^{infty}(mathbb R^n))_{theta,infty} =W!H^{p(cdot)/(1-theta)}(mathbb R^n),quad thetain(0,1), end{equation*} where $W!H^{p(cdot)/(1-theta)}(mathbb R^n)$ denotes the variable weak Hardy space. As an application, the variable weak Hardy space $W!H^{p(cdot)}(mathbb R^n)$ with $p_-:=mathopmathrm{ess,inf}_{xinrn}p(x)in(1,infty)$ is proved to coincide with the variable Lebesgue space $W!L^{p(cdot)}(mathbb R^n)$.