多进小波展开的Gibbs函数的渐近性质

本文研究了一类多进小波展开的Gibbs函数的渐近性质,特别地,包括了多进Daubechies型小波．     

正交小波展开的Gibbs现象

近十年来，随着小波理论和应用的迅猛发展，对于小波的Gibbs现象也吸引了来自不同领域的研究兴趣。这是因为在某些应用领域中，特别是在信号处理和图像处理的应用中，这一现象影响了预期的效果。研究们对减弱和消除这一现象付出了许多努力。这篇章主要讨论和总结了在小波的离散正交展开中的Gibbs现象，章强调了summability方法的最近发展并对于其他方法和结果列出了参考献，章在最后讨论了正在研究中的一些有待于解决的相关问题。     

具有二阶消失矩的多进制对称Coiflet小波基

本文研究了具有二阶消失矩的多进制对称Coiflet小波的构造方法,分析了它们的特征,并给出了算例。     

一种具有消失矩的小波基的构造

在N≥2情况下构造了一种性质良好的小波母函数,这种小波母函数N阶可导并且趋于零的阶数为O|t|-N(|t|→∞),同时具有N-2阶消失矩和某种对称性.文章还就N=4的情况给出了计算实例.     

多尺度函数与多小波的构造

在多小波和单小波的基础上利用矩阵卷积构造出了一类多尺度函数与多小波,并通过实例对构造算法加以说明.     

a尺度正交多尺度函数和正交多小波

基于a 尺度正交单尺度函数,分别给出重数为2和3的a 尺度正交多尺度函数的构造算法。并给出对应正交多小波的显式构造。最后给出伸缩因子为3的正交多小波的构造算例。     

二进小波的构造方法研究

提出两种二进小波的构造方法．首先,将Mallat构造的B-样条二进小波推广得到一种构造B-样条二进小波的新方法;其次,基于二进提升方案提出构造二进小波的另一种新方法一构造定理,并通过调整定理中提升参数的形式、以新的B-样条二进小波作为初始二进小波,具体构造了具有有限长单位脉冲响应、高阶消失矩、线性相位的提升二进小波,这些提升二进小波不能由Sweldens提升方案得到．     

Hermite展开与弱函数乘法的性质

根据丁夏畦院士利用Hermite展开定义的弱函数和广义弱函数以及函数的乘法等概念,来进一步研究弱函数乘法的相关性质,并证明了弱函数的乘法满足交换律、分配律和Leibniz法则,但不满足结合律。     

基于消失矩的多带Cofilet型小波的构造

本文通过研究多带对称小波完全重构、线性相位以及消失矩性质,提出了多带Cofilet型小波的一种简单构造方法,数值试验表明了理论的正确性与算法的简单特性。     

Representation of congruences on regular semigroups with inverse transversals

For a regular semigroup with an inverse transversal, we have Saito’s structureW(I,S ^o, Λ, *, {α, β}). We represent congruences on this kind of semigroups by the so-called congruence assemblage which consist of congruences on the structure component partsI,S ^o and Λ. The structure of images of this type of semigroups is also presented. This work is supported by Natural Science Foundation of Guangdong Province     

Structure globale des extensions regulieres galoisiennes

A natural characterization of known types of inverse transversal leads to the introduction of several new types, which we characterize in a similar natural way. Relations between the various types produce a general classification. We also determine for which types of inverse transversal considered the congruence extension property holds.     

INVERSE TRANSVERSALS ARE MUTUALLY ISOMORPHIC

It has been suspected for some time that if a regular semigroup S has an inverse transversal then all inverse transversals of S are isomorphic. Here we give a proof of this fact.     

Naturally ordered regular semigroups with an inverse monoid transversal

The notion of an inverse transversal of a regular semigroup is well-known. Here we investigate naturally ordered regular semigroups that have an inverse transversal. Such semigroups are necessarily locally inverse and the inverse transversal is a quasi-ideal. After considering various general properties that relate the imposed order to the natural order, we highlight the situation in which the inverse transversal is a monoid. The regularity of Green’s relations is also characterised. Finally, we determine the structure of a naturally ordered regular semigroup with an inverse monoid transversal.     

Associate inverse subsemigroups of regular semigroups

By an associate inverse subsemigroup of a regular semigroup S we mean a subsemigroup T of S containing a least associate of each x∈S, in relation to the natural partial order ≤ _S . We describe the structure of a regular semigroup with an associate inverse subsemigroup, satisfying two natural conditions. As a particular application, we obtain the structure of regular semigroups with an associate subgroup with medial identity element. Research supported by the Portuguese Foundation for Science and Technology (FCT) through the research program POCTI.     

带逆断面的正则半群上的强模糊同余

带逆断面的正则半群是一类重要的正则半群.就带逆断面的正则半群类引入强模糊同余的概念,进而用所谓的强模糊同余三元组抽象地刻画带逆断面的正则半群上的强模糊同余.     

完全单半群及完全正则半群的逆断面

指出完全单半群Ｓ的任何一个Ｆ－类是逆断面,且为Ｑ－逆断面,而Ｓ的任何一个逆断面必是一个Ｆ－类,因而所有逆断面同构。并且给出完全正则半群的逆断面存在的充要条件。