两类离散哈密顿系统极限点型的判定

利用算子的谱理论及经典的不等式,讨论两类离散哈密顿系统,得出半退化型系统为强极限点型以及Dirac型系统为极限点型的一些判别准则．     

离散哈密顿系统极限圆型及非极限圆型的判定

讨论了高阶离散哈密顿系统的亏指数问题,得到了该系统是极限圆型的充要条件,并且在此基础上给出了半退化型和Dirac型离散哈密顿系统是非极限圆型的判别准则.     

Orlicz空间鞅算子不等式(英文)

在本文中我们研究了由具有弱(p,p)型和(∞,∞)型的鞅算子T所推广鞅Orlicz空间,而鞅算子T是经典鞅论中极大算子M和均方算子S的推广.为了说明具有弱(p,p)型和(∞,∞)型的鞅算子T的存在性,我们引进了鞅算子Mp.利用鞅算子Mp,我们得到了鞅算子的双Φ不等式的最优条件,而且我们还得到了鞅算子Mp的Doob不等式.     

一类四阶离散哈密顿系统周期解的存在性

本文研究了一类四阶离散哈密顿系统周期解的存在性问题.利用临界点理论中的极大极小方法,通过引入两个不同的控制函数,得到了新的可解性条件,并且利用这些条件得到了新的存在性结果.     

CFI算子和Weyl型定理(英文)

广义(ω)性质是Weyl定理的一种变形,它推广了由Rakocevic在[Matematicki Vesnik,1985,37(4):423-426]中引入的(ω)性质.本文利用一致Fredholm算子指标性质(CFT),给出了Hilbert空间上的有界线性算子满足广义(ω)性质的充要条件.另外还利用这一性质考虑了广义(ω_1)性质和(ω_1)性质的等价性.     

离散哈密顿系统多个周期解的存在性

本文利用临界点理论,建立了一类离散哈密顿系统存在多个周期解的一些充分条件.     

黎曼流形上散度型算子的低阶特征值估计(英文)

本文研究黎曼流形上散度型算子的低阶特征值.利用Rayleigh-Ritz不等式,得到了这种算子的低阶特征值所满足的一个不等式.而且,对于拉普拉斯算子的低阶特征值,本文的结果是最佳的.     

(h)性质的一个新刻画（英文）

本文利用广义Kato性质诱导的谱集,研究了Weyl定理的一种新变形,称其为(h)性质,并证明了(h)性质如何根据该谱集性质得到.同时给出了直和算子T⊕S满足(h)性质的条件.此外,利用该诱导谱集研究了Banach空间上的有界算子T在与T交换的幂有限秩算子扰动下的(h)性质稳定性.     

强K(a)hler-Finsler流形上(p,q)形式的中值Laplace算子

本文给出了强K(a)hler-Finsler流形上中值Laplace算子的一些性质,如自伴性质,散度形式等.与K(a)hler流形上利用逆变基本张量[11]及其在Finsler流形上的变形[5,10]作为密度函数定义流形上的逐点内积及整体内积不同,作者利用强K(a)hler-Finsler流形上的逆变密切Kahler度量作为密度函数定义了流形上的逐点内积和整体内积,并定义了强K(a)hler-Finsler流形上的Hodge-Laplace算子,它可看作函数情形中值Laplace算子的推广.     

关于(A,B)型算子理想

对Gonz(?)lez和Martinon A新近建立的(A,B)型算子理想作进一步讨论,证明对任一算子理想B,(L,B)都是闭、满射的算子理想.证明对严格奇异算子理想S,(L,S)就是S的闭、满射包,也就是Rosenthal算子理想.     

Spectral properties of singular discrete linear Hamiltonian systems

This paper is concerned with spectral properties of singular discrete linear Hamiltonian systems. It is shown that properties of the essential spectrum of each self-adjoint subspace extension (SSE) of the corresponding minimal subspace are independent of the values of the coefficients of the system on any finite subinterval. The analyticity of the Weyl function is studied by employing the Schwarz reflection principle for the system in the limit point case. Based on the above work, several sufficient conditions are obtained for each SSE to have no essential spectrum points in an interval of the real line in the strong limit point case, and then a sufficient condition for the essential spectrum to be bounded from below (above) and a sufficient condition for the pure discrete spectrum are presented, respectively. As a direct consequence, the related spectral properties of singular higher order symmetric vector difference expressions are given.     

Limit Point, strong limit point and Dirichlet conditions for discrete Hamiltonian systems

This paper deals with discrete Hamiltonian systems with a singular endpoint. The limit point condition, the strong limit point condition and the Dirichlet condition are studied based on asymptotic behaviors or square summabilities in the maximal domains. The equivalence between the limit point and strong limit point conditions is established for a class of such systems; and for degenerated Hamiltonian system, the three conditions are shown to imply each other.     

STRONG LIMIT POINT FOR LINEAR HAMILTONIAN DIFFERENCE SYSTEM

The definition of strong limit-point for singular Hamiltonian difference expressions with complex coefficients are given, and some strong limit-point criteria are established.     

迁移算子离散本征值及其聚点的分布

讨论了各向异性、能量相关、非均匀有界凸体介质中迁移算子的谱,在省略某些不符合实际的 特殊条件的情况下,对这类算子离散本征值及其聚点的位置分布,同样获得了一个类似的结果.     

极限圆型Hamilton算子乘积的自伴性

本文讨论了极限圆型Hamilton算子乘积的自伴性,利用Calkin方法及奇异Hamilton系统自伴扩张的一般构造理论,给出了在极限圆型时判定Hamilton算子乘积自伴的一个充要条件.     

Symplectic Structure of Discrete Hamiltonian Systems

This paper is concerned with the symplectic structure of discrete nonlinear Hamiltonian systems. The results are related to an open problem that was first proposed by C. D. Ahlbrandt [J. Math. Anal. Appl.180 (1993), 498-517] discussed elsewhere in the literature. But we give a different statement and different proof. Under a solvable condition, we show that the solution operator of a discrete nonlinear Halmiltonian system is symplectic. Then its phase flow is a discrete one-parameter family of symplectic transformations and preserves the phase volume.     

具有中间亏指数的线性哈密顿算子的点谱

本文讨论具有任意亏指数d的自伴线性哈密顿算子点谱与对应的线性哈密顿系统的平方可积解之间的关系.若对于某个实开区间中的任意点λ,系统总有d个线性无关解,则它的任何自伴算子的点谱在这个开区间上是不稠密的.     

Non-limit-circle criteria for singular Hamiltonian differential systems

Non-limit-circle criteria for singular Hamiltonian differential expressions with complex coefficients are obtained. The main results are extensions of the previous limit-point criterion due to H. Weyl for second-order differential equations.