弱奇异l-群的结构

引入弱奇异元及弱奇异l-群的概念，通过建立弱奇异元及弱奇异l-群的刻划，研究了一般弱奇异l-群的性质及相关的结构，部分地改进了有关奇异l-群已有的结果．     

l-群的极大下子群

在非正规值的条件下,给出l-群极大下子群的唯一表达形式,由此推广[1]中的一个结果.与此同时,建立了正规值l-群,特殊值l-群及有限值l-群之间等价的一个充要条件.     

局部紧Vilenkin群上弱Morrey-Herz空间中一些算子的有界性

首先引入了一个新空间—局部紧Vilenkin群G上弱齐次Morrey-Herz空间WMK_(p,q)~(α,λ)(G),然后在WMK_(p,q)~(α,λ)(G)上讨论了一些奇异积分算子和分数次奇异积分算子的有界性问题.     

局部紧Vilenkin群上权BMOα空间与奇异积分

已有一些论文讨论局部域上奇异积分关于Lebesgue空间,Hardy空间及BMO空间上的有界性,本文讨论了局部紧Vilenkin群上一类奇异积分的权BMOα空间的有界性。给出了主值奇异积分的BMOα空间的有界性定理。     

特殊值l—群的l—同态象及l—扩张性

本研究了特殊值l-群的一类特殊的l-同态象及l-扩张闭性。在非超Archimedean的条件下，证明了l-群G是特殊值的当且仅当对于G的每个闭l-理想K，G／K与K均是特殊值的。     

特殊值l-群的l-同态象及l-扩张性

本文研究了特殊值 l-群的一类特殊的 l-同态象及 l-扩张闭性 .在非超 Archimedean的条件下 ,证明了 l-群 G是特殊值的当且仅当对于 G的每个闭 l-理想 K,G/ K与 K均是特殊值的 .     

单位圆内亚纯函数的奇异点

本文对单位圆内零级亚纯函数得到了一个较为广泛的与正规定则相应的奇异点的存在性,并由此得到如下结果：若单位圆|z|＜1内的亚纯函数满足则存在点eiθ0（≤θ0＜2π）使得对任意正数ε＞0任意正整数。n≥1,恒有limr→l-0n（r,θ0,ε;flfm=a）=＋∞对每一有穷非零复数a成立．     

格序向量空间的同构

研究了 l-向量空间的凸同余关系、同构关系 ,将 l-群的同构定理推广到 l-向量空间 .     

奇异系统的某些性质及其与奇异脉冲系统的稳定性等价

本文研究了与特征值相关的奇异系统解的构造及其性态，并讨论了奇异脉冲系统与奇异系统的稳定性等价。     

Heisenberg型群上的强奇异卷积算子——献给陆善镇教授75华诞

本文将给出Heisenberg型群上的一些强奇异卷积算子的L^2有界性.特别地,本文的结果改进并推广了Laghi和Lyall在Heisenberg群上的相应工作.此外,一些更简单、有效的技巧也在本文中引入.     

Using cross-product matrices to compute the SVD

This paper concerns accurate computation of the singular value decomposition (SVD) of an matrix . As is well known, cross-product matrix based SVD algorithms compute large singular values accurately but generally deliver poor small singular values. A new novel cross-product matrix based SVD method is proposed: (a) Use a backward stable algorithm to compute the eigenpairs of and take the square roots of the large eigenvalues of it as the large singular values of ; (b) form the Rayleigh quotient of with respect to the matrix consisting of the computed eigenvectors associated with the computed small eigenvalues of ; (c) compute the eigenvalues of the Rayleigh quotient and take the square roots of them as the small singular values of . A detailed quantitative error analysis is conducted on the method. It is proved that if small singular values are well separated from the large ones then the method can compute the small ones accurately up to the order of the unit roundoff . An algorithm is developed that is not only cheaper than the standard Golub–Reinsch and Chan SVD algorithms but also can update or downdate a new SVD by adding or deleting a row and compute certain refined Ritz vectors for large matrix eigenproblems at very low cost. Several variants of the algorithm are proposed that compute some or all parts of the SVD. Typical numerical examples confirm the high accuracy of our algorithm.Supported in part by the National Science Foundation of China (No. 10471074).     

On the unsolvability of inverse singular value problems almost everywhere

In this paper, the unsolvability of inverse singular value problems almost everywhere is discussed. Applying the method described by Sun and Ye [J Comput Math. 1986;4:212–226], a sufficient condition is given such that the inverse singular value problems are unsolvable almost everywhere. This result shows that inverse singular value problems are unsolvable almost everywhere if the multiplicity of zero singular values is sufficiently large.     

On the order of singular optimal control problems

In singular optimal control problems, the functional form of the optimal control function is usually determined by solving the algebraic equation which results by successively differentiating the switching function until the control appears explicitly. This process defines the order of the singular problem. Order-related results are developed for singular linear-quadratic problems and for a bilinear example which gives new insights into the relationship between singular problem order and singular are order.Dedicated to R. BellmanThis work was supported by the National Science Foundation under Grant No. ENG-77-16660.     

Sensitivity analysis for the generalized singular value decomposition

In this paper, we discuss the sensitivity of multiple nonzero finite generalized singular values and the corresponding generalized singular matrix set of a real matrix pair analytically dependent on several parameters. From our results, the partial derivatives of multiple nonzero singular values and their left and right singular vector matrices are obtained.Copyright © 2012 John Wiley & Sons, Ltd.     

Singular integral on bounded strictly pseudoconvex domain

Kytmanov and Myslivets gave a special Cauchy principal value of the singular integral on the bounded strictly pseudoconvex domain with smooth boundary. By means of this Cauchy integral principal value, the corresponding singular integral and a composition formula are obtained. This composition formula is quite different from usual ones in form. As an application, the corresponding singular integral equation and the system of singular integral equations are discussed as well.     

矩阵奇异值的极值性质

讨论了矩阵奇异值的问题,利用奇异值分解定理给出了奇异值的极值性质,并用其证明了矩阵论中关于奇异值的一些经典结论.     

On the singular PDE's geometry and boundary value problems

A geometric formulation of singular partial differential equations (PDEs) is considered. Surgery techniques and integral bordism groups are utilized, following previous works by Prástaro on PDEs, in order to build global solutions crossing also singular points and to study their stability properties.     

同宿流形中的奇异轨道

研究较一般的高维退化系统的同宿、异宿轨道分支问题．利用推广的Melnikov函数、横截性理论及奇摄动理论，对具有鞍—中心型奇点的带有角变量的奇摄动系统，在角变量频率产生共振的情况下，讨论其同宿、异缩轨道的扰动下保存和横截的条件．推广和改进了一些文献的结果。     

Constructive factorizations of unitons via singular Darboux transformations

Some new factorizations of unitons into Lie groups are established via singular Darboux transformations. The factorization processes for Grassmannian unitons are also considered. Furthermore, a purely algebraic method for constructing Grassmannian unitons is presented.