一类四元素数字集的正交函数的个数

自仿测度的谱与非谱问题近年引起了很大的关注,关于自仿测度的非谱问题,其中之一就是要估算它在L2空间上的正交指数的个数．通过对μM,D傅里叶变换的零点集性质的分析和讨论,对现有的结论进行了改进,确定了相应四元素数字集的平面自仿测度在L2的空间上正交指数函数的最大个数为3．     

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.     

空间自仿测度下无限正交指数系存在的条件

自仿测度μ_M,D的谱与非谱问题是自仿测度谱理论研究的主要内容之一,而μ_M,D-正交指数系的有限性或无限性问题在研究自仿测度是否为谱测度中起着重要的作用.本文主要探讨空间自仿测度下无限正交指数系存在的条件.通过利用函数m_D(x)零点集Z(m_D)中的非零中间点(即坐标为0或1/2的点)的性质,得到存在无限μ_(M,D)-正交指数系的许多条件,为进一步研究自仿测度μ_(M,D)的谱性质奠定基础.     

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.     

空间Sierpinski垫上的五元素正交指数系

设p_1,p_2,p_3∈Z\{0,±1},e_1,e_2,e_3是R~3上标准的单位正交基,由扩张矩阵M=diag[p_1,p_2,p_3]和数字集D={0,e_1,e_2,e_3}确定的自仿测度μM,D是支撑在空间Sierpinski垫T(M,D)上,其对应的Hilbert空间L~2(μM,D)上正交指数系的有限性与无限性问题已经解决.在有限的情形下,空间L~2(μM,D)上正交指数系基数的最佳上界为"4"的猜测还未完全解决.本文构造出了此空间上一列五元素正交指数函数系,说明上述最佳上界为"4"的猜测是错误的.     

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.     

R~n中一类具有N元数字集的自仿测度的谱性

假设R∈M_n(Z)为扩张矩阵和N元数字集D={0,a_1,a_2,…,a_(N-1)}u≡{0,1,…,N-1}u (modN),这里u∈Z~n\{0}.该文主要研究由D和R生成的自仿测度μ_(R,D)的谱性,得到了μ_(R,D)为谱测度的一个充分条件.对于一些特殊情况,得到了μ_(R,D)为谱测度的一个充分必要条件,并给出其谱的具体表达式.     

关于Strichartz的一个谱对准则

研究了与压缩迭代函数系和扩张迭代函数系相关的自仿测度的谱性质.在和谐对的条件下,分别确定了谱对形成的一些充分条件和必要条件.首先,给出了Strichartz谱对准则的几个等价形式.其次,得到了这个谱对成立的两个必要条件.最后,提供了Strichartz谱对准则的一个严格而详细的证明.     

非谱自仿测度下正交指数函数系的基数

设μ_(M,D)是由扩张矩阵M∈M_n(Z)和有限数字集D?Z~n通过仿射迭代函数系统{φ_d(x)=M~(-1)(x+d)}_(d∈D)唯一确定的自仿测度,它的非谱性与相应的平方可积函数构成的Hilbert空间L~2(μ_(M,D))中正交指数函数系的有限性或无限性密切相关.通过对数字集D的符号函数m_D(x)的零点集合Z(m_D)的特征分析以及其中非零中间点(即坐标为0或1/2的点)和非中间点的性质应用,得到了非谱自仿测度下正交指数函数系基数的一个更为精确的估计,改进推广了Dutkay,Jorgensen等人的相关结果.     

毕达哥拉斯模糊软集的相似性测度及其应用

直觉模糊软集不能处理隶属度与非隶属度之和大于1的情况,且现有的直觉模糊软集的相似性测度只考虑了隶属度与非隶属度,忽视了犹豫度。针对以上问题,本文提出了一种基于隶属度、非隶属度以及犹豫度三个参数的毕达哥拉斯模糊软集的相似性测度和加权相似性测度。在为加权相似性测度的权重取值时,本文基于现有文献中直觉模糊熵存在的缺陷建立一种改进的直觉模糊熵,利用熵权法计算权重。分别讨论两相似性测度公式的性质,最后将两相似性侧度公式应用在建筑材料的模式识别问题中。     

On a class of self-similar processes with stationary increments in higher order Wiener chaoses

We study a class of self-similar processes with stationary increments belonging to higher order Wiener chaoses which are similar to Hermite processes. We obtain an almost sure wavelet-like expansion of these processes. This allows us to compute the pointwise and local Hölder regularity of sample paths and to analyse their behaviour at infinity. We also provide some results on the Hausdorff dimension of the range and graphs of multidimensional anisotropic self-similar processes with stationary increments defined by multiple Wiener–Itô integrals.     

A REPRESENTATION FORMULA RELATED TO SCHR(O)DINGER OPERATORS

Schr(o)dinger operator is a central subject in the mathematical study of quantum mechanics.Consider the Schrodinger operator H = -△ V on R, where △ = d2/dx2 and the potential function V is real valued. In Fourier analysis, it is well-known that a square integrable function admits an expansion with exponentials as eigenfunctions of -△. A natural conjecture is that an L2 function admits a similar expansion in terms of "eigenfunctions" of H, a perturbation of the Laplacian (see [7], Ch. Ⅺ and the notes), under certain condition on V.     

On a class of Riemann surfaces

It is considered the class of Riemann surfaces with dimT1 = 0, where T1 is a subclass of exact harmonic forms which is one of the factors in the orthogonal decomposition of the spaceΩH of harmonic forms of the surface, namely The surfaces in the class OHD and the class of planar surfaces satisfy dimT1 = 0. A.Pfluger posed the question whether there might exist other surfaces outside those two classes. Here it is shown that in the case of finite genus g, we should look for a surface S with dimT1 = 0 among the surfaces of the form Sg\K , where Sg is a closed surface of genus g and K a compact set of positive harmonic measure with perfect components and very irregular boundary.     

CONTENTS OF VOLUME 30

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Instructions for contributions

正Applied Mathematics-A Journal of Chinese Universities,Series B(Appl.Math.J.Chinese Univ.,Ser.B)is a comprehensive applied mathematics journal jointly sponsored by Zhejiang University,China Society for Industrial and Applied Mathematics,and Springer-Verlag.It is a quarterly journal with     

Journal of Mathematical Research with Applications Guide for Authors

正Journal overview:Journal of Mathematical Research with Applications(JMRA),formerly Journal of Mathematical Research and Exposition(JMRE)created in 1981,one of the transactions of China Society for Industrial and Applied Mathematics,is a home for original research papers of the highest quality in all areas of mathematics with applications.The target audience comprises:pure and applied mathematicians,graduate students in broad fields of sciences and technology,scientists and engineers interested in mathematics.     

Staircase transportation problems with superadditive rewards and cumulative capacities

A cumulative-capacitated transportation problem is studied. The supply nodes and demand nodes are each chains. Shipments from a supply node to a demand node are possible only if the pair lies in a sublattice, or equivalently, in a staircase disjoint union of rectangles, of the product of the two chains. There are (lattice) superadditive upper bounds on the cumulative flows in all leading subrectangles of each rectangle. It is shown that there is a greatest cumulative flow formed by the natural generalization of the South-West Corner Rule that respects cumulative-flow capacities; it has maximum reward when the rewards are (lattice) superadditive; it is integer if the supplies, demands and capacities are integer; and it can be calculated myopically in linear time. The result is specialized to earlier work of Hoeffding (1940), Fréchet (1951), Lorentz (1953), Hoffman (1963) and Barnes and Hoffman (1985). Applications are given to extreme constrained bivariate distributions, optimal distribution with limited one-way product substitution and, generalizing results of Derman and Klein (1958), optimal sales with age-dependent rewards and capacities.To our friend, Philip Wolfe, with admiration and affection, on the occasion of his 65th birthday.Research was supported respectively by the IBM T.J. Watson and IBM Almaden Research Centers and is a minor revision of the IBM Research Report [6].