SearcharxivSearch

arXiv · math/0608200

Simultaneous Translational and Multiplicative Tiling and Wavelet Sets in R^2

Abstract

Simultaneous tiling for several different translational sets has been studied rather extensively, particularly in connection with the Steinhaus problem. The study of orthonormal wavelets in recent years, particularly for arbitrary dilation matrices, has led to the study of multiplicative tilings by the powers of a matrix. In this paper we consider the following simultaneous tiling problem: Given a lattice in $Ł\in \R^d$ and a matrix $A\in\GLd$, does there exist a measurable set $T$ such that both $\{T+α: α\inŁ\}$ and $\{A^nT: n\in\Z\}$ are tilings of $\R^d$? This problem comes directly from the study of wavelets and wavelet sets. Such a $T$ is known to exist if $A$ is expanding. When $A$ is not expanding the problem becomes much more subtle. Speegle \cite{Spe03} exhibited examples in which such a $T$ exists for some $Ł$ and nonexpanding $A$ in $\R^2$. In this paper we give a complete solution to this problem in $\R^2$.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Eugen J. Ionascu, Yang Wang. 2006-08-08. Simultaneous Translational and Multiplicative Tiling and Wavelet Sets in R^2. https://arxiv.org/abs/math/0608200

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

Average Chord Lengths in a Triangle

Let $P$ be a point inside a triangle $T$. We consider the average length of the chords of $T$ through $P$, where the direction of the chord is chosen uniformly. An elementary formula is obtained in terms of the distances from $P$ to the sides and vertices of the triangle. Several classical triangle centers give especially simple specializations. For example, if $I$ is the incenter, then \[ M_T(I)=\frac{2r}{\pi} \log\left(\cot\frac A4\cot\frac B4\cot\frac C4\right). \] Our main result is the sharp inequality \[ M_T(P)\le \frac{p}{\pi\sqrt3}\log(2+\sqrt3), \] valid simultaneously for every triangle of perimeter $p$ and every interior point $P$. Thus, among all such pairs $(T,P)$, the largest possible average chord length occurs only when $T$ is equilateral and $P$ is its center. The proof is an elementary symmetrization argument. We close with brief remarks relating the problem to the radial center of a convex body, the electrostatic potential center of a triangle, and dual quermassintegrals.

math.GM

A Proof of Liu's Conjecture on the Fundamental Triangle Inequality

Let $a,b,c$ be the side lengths of a triangle, and let $R$ and $r$ denote its circumradius and inradius, respectively. We prove a conjecture of Liu stating that \[\sum_{\mathrm{cyc}} \left(\frac{a(b+c-a)}{bc}\right)^k \geq 2+\left(\frac{2r}{R}\right)^k,~~k>1, \] with the reverse inequality for $0<k<1$. The proof reduces the problem to three positive variables with fixed sum and product. We also determine the equality cases.

math.GM