四分Cantor测度的谱性质

自仿测度μM,D谱性质的研究始于四分Cantor测度μ4(即M=4,D={0,2}的情形).在长期从事谱集研究的基础上,Jorgensen和Pedersen在1998年首次发现μ4是一个具有谱性质的分形测度,其谱Λ(M,S)与和谐对(M~(-1)D,S)密切相关,其中S={0,1}.近年来的研究表明,对于某些奇数l,数乘集合lΛ(M,S)也是测度μ4的谱.这使得测度μ4的一些谱具有较强的稀疏性.本文重点对具有上述性质的奇数l进行讨论.利用数论中同余关系和有限群中元素的阶的性质,得到当l分别为素数、素数幂和素数乘积时,lΛ(M,S)为谱的判别依据,改进推广Dutkay等人的工作.     

由度量诱导的集合列上(下)极限及其应用

从数列上(下)极限出发,引入并研究由度量诱导的集合列上(下)极限,证明通常的集合列上(下)极限本质上是由离散度量诱导的上(下)极限,并且Lebesgue测度关于由度量诱导的集合列极限保持一定的连续性.     

新序结构下函数列的伪依集值模糊测度收敛

在m维正欧氏空间中引入一种新序结构,并由此序结构在集值模糊测度空间上给出可测函数序列伪依集值模糊测度收敛、(伪)依集值模糊测度几乎处处收敛、PS性和PS'性等概念,进而研究了伪依模糊测度收敛和(伪)几乎处处收敛之间的关系,获得相应的Lebesgue定理和Riesz定理.     

实变函数反例研究(Ⅰ)

在一般测度积分(非Lebesgue测度与积分)的框架下构造了实变函数中的多个反例.它们说明不同概念之间的区别,以及一些常用结论在缺乏相应的条件之后不再成立.这有力地补充了教材[1].     

数字集的谱性与谱自仿测度

本文主要确定与谱自仿测度μ_(M,D)相关的数字集D的谱性.研究所涉及的谱性问题与Dutkay、Han和Jorgensen的一个猜测密切相关.此猜测表明,在一维情形下,如果μ_(M,D)是谱自仿测度,则相应的数字集D总是一个谱集.对于一个自仿测度μ_(M,D),本文获得使数字集D具有谱性的一些条件,为这个猜测的成立提供了依据.另外,本文所得的结果在某些情形下也推广许多已知的相应结果.     

模糊复测度空间上可测函数列几种收敛性之间的关系

作为经典复测度和模糊测度的推广,研究模糊复测度及模糊复测度空间上可测函数列几种收敛性之间的关系.在模糊复测度空间上得到了Egoroff定理、Lebesgue定理和Riesz定理等重要结果.为模糊复分析的深入研究打下一定基础.     

自仿测度的非谱准则

设μ_(M,D)是由仿射迭代函数系{φ_d(x)=M~(-1)(x+d)}_(d∈D)唯一确定的自仿测度,它的谱性或非谱性与Hilbert空间L~2(μ_(M,D))中正交指数基(也称为Fourier基)的存在性有着直接的关系.近年来自仿测度μ_(M,D)的谱性或非谱性问题的研究受到人们普遍的关注.本文给出了判定自仿测度μ_(M,D)非谱性的几个充分条件,所得结果改进推广Dutkay,Jorgensen等人的非谱准则.     

关于自保形测度与Lebesgue测度的等价性

本文我们研究了自保形测度与Lebesgu测度的关系,对Yuvla Peres等的结果进行了推广,证明了自相似测度要么是奇异的,要么关于Lebesgue测度 绝对连续的,并且若将Lebesgue测度限制在自相似测度的紧支撑上,则其关于非奇异的自相似测度是绝对连续的。     

含有不可数个无界变差点的一维连续函数

在单位区间[0,1]上构造了图像长度为无穷的一维连续函数.该函数含有不可数个但Lebesgue测度为0的无界变差点.所有无界变差点组成的集合中每一点皆为该集合的聚点.     

非二重性拟度量测度空间中修正的极大函数定理及其应用

主要研究了拟度量测度空间(X,d,μ)中修正的极大函数,其中X表示集合,μ表示不满足二重性的Borel测度,d表示不满足对称性的拟度量,本文对修正的极大函数建立了弱(1,1)估计和(Φ,Φ)型估计,其中Φ比N函数更一般.作为应用,证明了拟度量测度空间中推广的Lebesgue微分定理.本文的结果也适用于与常系数Kolmogorov型算子对应的Lie群G=(R~(N+1),o).     

Duality properties between spectra and tilings

Spectra and tilings play an important role in analysis and geometry respectively.The relations between spectra and tilings have bafied the mathematicians for a long time.Many conjectures,such as the Fuglede conjecture,are placed on the establishment of relations between spectra and tilings,although there are no desired results.In the present paper we derive some characteristic properties of spectra and tilings which highlight certain duality properties between them.     

On characterizations of spectra and tilings

In a recent paper, Lagarias, Reeds and Wang established a characterization of spectra and tilings that can be used to prove a conjecture of Jorgensen and Pedersen by Keller's criterion. Different techniques to prove these facts have also been developed by Kolountzakis, Iosevich and Pedersen. The primary aim of this paper is to present an elementary method of describing certain characterizations of spectra and tilings. To illustrate this method, we first give a simple proof of this characterization. We then use the method to derive some characteristic results connected with the dual Fuglede's spectral-set conjecture. The results here extend several known conclusions in a simple manner.     

Entropy numbers and lattice arrangements in l∞ (Γ)

The Banach spaces l_∞(Γ) admit tilings by balls of equal size that are arranged along a lattice. We present classes of bounded sets in spaces l_∞(Γ) whose optimal packings and covers in the sense of inner and outer metric entropy numbers are realized by lattice arrangements. © 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim     

On a characterization of spectra and tilings

Lagarias et al. (Duke Math. J. 103 (2000) 25-37) established a characterization of spectra and tilings that can be used to prove a conjecture of Jorgensen and Pedersen (J. Fourier Anal. Appl. 5 (1999) 285-302) by Keller's criterion. Different techniques to prove these facts have also been developed by Iosevich and Pedersen and Kolountzakis. In this expository article, the author presents an elementary approach to obtain a more general form of this characterization that relates spectra and tilings.     

On Uncountable Unions and Intersections of Measurable Sets

We consider several natural situations where the union or intersection of an uncountable family of measurable (in various senses) sets with a good additional structure is again measurable or may fail to be measurable. We primarily deal with Lebesgue measurable sets and sets with the Baire property. In particular, uncountable unions of sets homeomorphic to a closed Euclidean simplex are considered in detail, and it is shown that the Lebesgue measure and the Baire property differ essentially in this aspect. Another difference between measure and category is illustrated in the case of some uncountable intersections of sets of full measure (comeager sets, respectively). We also discuss a topological form of the Vitali covering theorem, in connection with the Baire property of uncountable unions of certain sets.     

Quasicrystallic Tilings and Projection Method

Basic notions related to quasiperiodic tilings and Delone sets in Eucledean space are discussed. It is shown how the cut and project method of constructing them is used to calculate their spectra. Special attention is paid to self-similar tilings and the way one can obtain one-dimensional substitutional tilings by the projection scheme. Bibliography: 18 titles.     

Minkowski content and fractal curvatures of self-similar tilings and generator formulas for self-similar sets

We study Minkowski contents and fractal curvatures of arbitrary self-similar tilings (constructed on a feasible open set of an IFS) and the general relations to the corresponding functionals for self-similar sets. In particular, we characterize the situation, when these functionals coincide. In this case, the Minkowski content and the fractal curvatures of a self-similar set can be expressed completely in terms of the volume function or curvature data, respectively, of the generator of the tiling. In special cases such formulas have been obtained recently using tube formulas and complex dimensions or as a corollary to results on self-conformal sets. Our approach based on the classical Renewal Theorem is simpler and works for a much larger class of self-similar sets and tilings. In fact, generator type formulas are obtained for essentially all self-similar sets, when suitable volume functions (and curvature functions, respectively) related to the generator are used. We also strengthen known results on the Minkowski measurability of self-similar sets, in particular on the question of non-measurability in the lattice case.     

多项式组的特征分解

任一多项式理想的特征对是指由该理想的约化字典序Grobner基G和含于其中的极小三角列C构成的有序对(G,C).当C为正则列或正规列时,分别称特征对(G,C)为正则的或正规的.当G生成的理想与C的饱和理想相同时,称特征对(G,C)为强的.一组多项式的(强)正则或(强)正规特征分解是指将该多项式组分解为有限多个(强)正则或(强)正规特征对,使其满足特定的零点与理想关系.本文简要回顾各种三角分解及相应零点与理想分解的理论和方法,然后重点介绍(强)正则与(强)正规特征对和特征分解的性质,说明三角列、Ritt特征列和字典序Grobner基之间的内在关联,建立特征对的正则化定理以及正则、正规特征对的强化方法,进而给出两种基于字典序Grobner基计算、按伪整除关系分裂和构建、商除可除理想等策略的(强)正规与(强)正则特征分解算法.这两种算法计算所得的强正规与强正则特征对和特征分解都具有良好的性质,且能为输入多元多项式组的零点提供两种不同的表示.本文还给出示例和部分实验结果,用以说明特征分解方法及其实用性和有效性.     

Spectral Self-Affine Measures on the Generalized Three Sierpinski Gasket

The self-affine measure μM,Dassociated with an iterated function system{φd(x)=M~(-1)(x + d)}_(d∈D) is uniquely determined. It only depends upon an expanding matrix M and a finite digit set D. In the present paper we give some sufficient conditions for finite and infinite families of orthogonal exponentials. Such research is necessary to further understanding the non-spectral and spectral of μM,D. As an application,we show that the L~2(μM,D) space has infinite families of orthogonal exponentials on the generalized three Sierpinski gasket. We then consider the spectra of a class of self-affine measures which extends several known conclusions in a simple manner.     

Measurability and the abstract Baire property

Within an abstract theory of point sets the author has successfully unified a substantial number of the analogous theorems concerning Lebesgue measure and Baire category. It has been shown that the Lebesgue measurable sets coincide with the sets having the abstract Baire property with respect to the family of all closed sets of positive Lebesgue measure and the question was raised in [2] whether the sets measurable with respect to certain Hausdorff measures were the same as the sets having the abstract Baire property with respect to the family of all closed sets of positive Hausdorff measure. In this article we establish a general theorem which, under the assumption of the continuum hypothesis, gives an affirmative answer to this question.