强连续双半群与积分双半群

本文研究积分双半群与有界线性算子双半群的关系,证明了Ｂａｎａｃｈ空间Ｘ上的指数有界积分双半群可以作为Ｘ的某个子空间上具有较强范数拓扑下的有界线性算了强连续双半 积分双半群也可作为较大空间上俱有较弱范数拓扑下的有界线性算子强连续双半群积分的限制,上述结果可以用来解释抽象边值问题的弱解的意义。     

线性算子双半群的扰动定理

本文研究有界线性算子强连续双半群的扰动问题。文中首先研究与强连续双半群母元有关的算子方程的可解性与算子的相似性。在此基础上证明了在一定条件下可化为指数衰减的强连续双半群经适当扰动后仍是一个可化为指数衰减的强连续双半群。     

Perturbation results for exponentially dichotomous operators on general Banach spaces

Some perturbation results for exponentially dichotomous operators are applied to prove the existence of stable and anti-stable solutions of Riccati equations associated to block operators on general Banach spaces, both for compact perturbations and for bisemigroups made up of immediately norm continuous semigroups.     

Free De Morgan Bisemigroups and Bisemilattices

We give a geometric representation of free De Morgan bisemigroups, free commutative De Morgan bisemigroups, and free De Morgan bisemilattices by using labeled graphs.2000 Mathematics Subject Classification: 08A70, 08B20This research was supported by the National Foundation of Scientific Research of Hungary under grant no. T30511.     

On the existence of strongly regular families of triangulations for domains with a piecewise smooth boundary

In this note we present an algorithm for a construction of strongly regular families of triangulations for planar domains with a piecewise curved boundary. Some additional properties of the resulting triangulations are considered.     

Strongly regular Cayley graphs and rationality of relative Gauss sums

In this note, we give a construction of strongly regular Cayley graphs. The presented construction is based on choosing cyclotomic classes in finite fields, and our results generalize ten of the eleven sporadic examples of cyclotomic strongly regular graphs given by Schmidt and White [B. Schmidt, C. White, All two-weight irreducible cyclic codes, Finite Fields Appl. 8 (2002), 321–367] into infinite families. These infinite families of strongly regular graphs have new parameters. The main tools that we employed are relative Gauss sums instead of explicit evaluations of Gauss sums.     

求解广义互补问题

1 引言 设为一闭凸锥,f是R~n到自身的一映射.广义互补问题,记作GCP(K,f),即找一向量x满足 GCP(K,f) x∈K,f(x)∈且x~Tf(x)=0,(1) 其中,是K的对偶锥(即对任一K中向量x,满足x~Ty≤0的所有y的集合).该问题首先 由Habetler和Price提出.当K=R_+~n(R~n空间的正卦限),此问题就是一般的互补问题.许多作者已经提出了很多求解线性或非线性互补问题的方法.例如:Dafermos,Fukushima,Harker和Price以及其它如参考文献所列.近年来,何针对单调线性变分不等式提出了一些投影收缩算法. Fang在函数是Lipschitz连续及强单调的条件下,在[3]给出一简单的迭代投影法,在[4]中给出一线性化方法去求解广义互补问题(1).在[3]中,他的迭代模式是     

Short Equational Bases for Two Varieties of Groupoids Associated with Involuted Restrictive Bisemigroups of Binary Relations

We sharpen the main results in [1] by finding short equational bases for two varieties of groupoids associated with involuted restrictive bisemigroups of binary relations. For the benefit of the reader we use the notation Bredikhin set in [1].     

On bounded time-dependent perturbations of operator cosine functions

In this note it is shown that the Cauchy problem associated with the infinitesimal generatorA of a strongly continuous operator cosine function remains uniformly well-posed under bounded time-dependent perturbations ofA.     

Invariant set criteria for CO semigroups

The purpose of this note is to describe conditions that guarantee the invariance of convex sets for strongly continuous semigroups of linear operators. The criteria is expressed in terms of subtangential properties of the semigroup and its infinitesimal generator. These ideas include various recent results of a similar nature.     

The dependence of extreme values of discrete and continuous time strongly dependent Gaussian processes

In this note, the asymptotic relation between the maximum of a continuous strongly dependent stationary Gaussian process and the maximum of this process sampled at discrete time points is studied. It is shown that these two extreme values are asymptotically totally dependent no matter what the grid of the discrete time points is.     

Controllability of second-order neutral functional differential inclusions in Banach spaces

In this paper, we prove the controllability of second-order neutral functional differential inclusions in Banach spaces. The result are obtained by using the theory of strongly continuous cosine families and a fixed point theorem for condensing maps due to Martelli.     

Continuous families of Riemannian manifolds, Isospectral on functions but not on 1-forms

The purpose of this paper is to present the first continuous families of Riemannian manifolds that are isospectral on functions but not on 1-forms, and, simultaneously, the first continuous families of Riemannian manifolds with the same marked length spectrum but not the same 1-form spectrum. Examples of isospectral manifolds that are not isospectral on forms are sparse, as most examples of isospectral manifolds can be explained by Sunada’s method or its generalizations, hence are strongly isospectral. The examples here are three-step Riemannian nilmanifolds, arising from a general method for constructing isospectral Riemannian nilmanifolds previously presented by the author. Gordon and Wilson constructed the first examples of nontrivial isospectral deformations, continuous families of Riemannian nilmanifolds. Isospectral manifolds constructed using the Gordon-Wilson method, a generalized Sunada method, are strongly isospectral and must have the same marked length spectrum. Conversely, Ouyang and Pesce independently showed that all isospectral deformations of two-step nilmanifolds must arise from the Gordon-Wilson method, and Eberlein showed that all pairs of two-step nilmanifolds with the same marked length spectrum must come from the Gordon-Wilson method. To the memory of Hubert Pesce, a valued friend and colleague.     

线性算子双半群及在间断和脉冲微分方程中的应用(英)

研究抽象Ｂａｎａｃｈ空间中线性微微分方程的可解性,利用算子双半群方法,讨论了在确定时间跳跃或脉冲的线性微分方程解的存在性,表明在一定条件下间断或脉冲方程的解存在唯一．     

The Spectral Mapping Theorem for Evlution Semigroups on L p Associated with Strongly Continuous Cocycles

In this note we prove the spectral mapping theorem for certain evolution semigroups. Specifically, we study the evolution semigroup on L^p(Theta,mu;X), 1≤p相似文献   

Note on symmetry and bifurcation near families of solutions

We give conditions for an orbit under continuous, but not everywhere differentiable action of a compact Lie group on a Banach space to have an invariant tubular neighborhood of a prescribed form. The result is important for the study of bifurcation problems near families of solutions. This note completes and corrects part of the earlier paper [6].     

Generalizations of a Theorem of Datko and Pazy

This note gives necessary and sufficient conditions for exponential stability of semigroups of linear operators in Banach spaces. Generalizations of a well-known result due to Datko, Pazy and Neerven are obtained for the case of semigroups of operators that are not strongly continuous.     

Controllability Results for Second Order Neutral Impulsive Integrodifferential Systems

In this paper, we address the problem of controllability for abstract second order neutral integrodifferential systems with impulsive conditions in Banach spaces. Furthermore, we discuss the controllability of second-order neutral integrodifferential systems in finite dimensional spaces. The results are obtained by using strongly continuous cosine families of operators and the Banach fixed point theorem.     

Cosine families and semigroups really differ

We reveal three surprising properties of cosine families, distinguishing them from semigroups of operators: (1) A single trajectory of a cosine family is either strongly continuous or not measurable. (2) Pointwise convergence of a sequence of equibounded cosine families implies that the convergence is almost uniform for time in the entire real line; in particular, cosine families cannot be perturbed in a singular way. (3) A non-constant trajectory of a bounded cosine family does not have a limit at infinity; in particular, the rich theory of asymptotic behaviour of semigroups does not have a counterpart for cosine families. In addition, we show that equibounded cosine families that converge strongly and almost uniformly in time may fail to converge uniformly.     

Strongly continuous M,N-families of bounded operators

Corresponding to the strong wellpssedness of the Cauchy problems for complete second order linear differential equations in Banach spaces, we introduce a notion of strongly continuous M, N-families and establish some basic results for these operator families.The project supported by National Science Fundation of China.