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1.
侯绳照  侯晋升 《数学杂志》1999,19(3):318-322
设X为Banach空间,B(X)为ZH 有界线性算子全体组成的代数,本文给出了B(X)上保k次幂弱连续线性满足射的完全刻划。  相似文献   

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Hadamard积和酉不变范数不等式   总被引:9,自引:0,他引:9  
詹兴致 《数学进展》1998,27(5):416-422
设Mn,m是n×m复矩阵空间,Mn≡Mn,n.对于Hermite阵G,H∈Mn,GH表示G-H半正定.记A和B的Hadamard积为AB.本文证明了若A,B∈Mn正定,而X,Y∈Mn,m任意,则(XA-1X)(YB-1Y)(XY)(AB)-1(XY),XA-1X+YB-1Y(X+Y)(A+B)-1(X+Y).这推广和统一了一些现存的结果.设‖·‖为任意酉不变范数,I是单位矩阵.本文还证明了对于X∈Mn,m和A∈Mn,B∈Mm,若AI,BI,则函数f(p)=‖ApX+XBp‖在[0,∞)上单调递增.  相似文献   

3.
王勤 《数学杂志》1997,17(4):468-472
记X为复数域上无限维Banach空间,H为无限维复可分Hilert空间。本文给出B(X)上保持点谱的满射可加射具有的形式,以及B(H)上某些初等算子保点谱的充要条件。  相似文献   

4.
王卿文 《数学进展》1996,25(6):532-539
设F和Ω分别是一个任意的体和一个具有对合反自同构的有限维中心代数且charΩ≠2.本研究体上的下列矩阵方程:AX-XB=C,(1)AX-XB=C,(2)AX+XB=-C(3)分别给出了在Ω上(1)有一般解,(2)自共轭解及(3)有斜自共轭解的充要条件,并将W.E.Roth的相似定理推广到了任意的体F上。  相似文献   

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本文给出了算子方程AXB-X=C可解的若干充要条件,其中(A,B)为下列情形之一:A或B有闭值域;A(B*)有闭值域并且是单射或者相似于一个协亚正规算子并且B(A*)是单侧移位;A+(B(*+))幂有界,其值域R(A+) R(A)(R(B) R(B+)并且B(A*)是单侧移位;A=U*且B=U是Hardy空间上重数为1的单侧移位.而且,给出了解的表达式.  相似文献   

6.
指数有界C-半群的共轭半群   总被引:7,自引:0,他引:7  
令S(t)是Banach空间X上的指数有界C-半群,S(t)是它在共轭空间X上的共轭半群.本文给出了X的一个闭子空间X+,使得S(t)在X+上的限制S+(t)是C|x+-半群,并给出了S+(t)的生成元.空间X+在某种意义上有极大性.  相似文献   

7.
独立随机变量序列重对数律的一个注记   总被引:1,自引:0,他引:1  
{X_i}为独立随机变量序列,E(X_i)<+∞,E(X (2)_(i))<+∞(i=1,2,…),当中心极限定理中的余项△n=O(ln Bnln ln Bn…(lnk Bn)~(1+δ)~(-1))时,本文得出结论:  相似文献   

8.
鲁世杰 《数学进展》1996,25(6):510-516
本文给出了算子方程AXB-X=C可解的若干充要条件,其中(A,B)为下列情形之一A或B有闭值域;A(B)有闭值域并且是单射或或进相似于一个协亚规算子并且B(A)是单侧移位;A^+(B^+)幂有界,其值域R(A^+)包含于R(A)(R(B)包含于R(B^+)并用B(A)是单侧移位;A=U且B=U是Hardy空间上重数为1的单侧移位,而且,给出了解的表达式。  相似文献   

9.
对于公式秩(AB)≤min[秩(A),秩(B)],本文结合线性方程组给出一种简捷的证法.引理如果线性方程组AX=θ的解都是BX=θ的解,则秩(A)≥秩(B).证不妨设AX=θ的基础解系含有n-秩(A)个线性无关解,BX=θ的基础解系含有m-秩(B)个...  相似文献   

10.
本文讨论离散时间代数Riccati方程ATXA-X-(ATXB+L)(R+BTXB)^-1(LT+BTXA)+Q=0的唯一对称正定解的上界和下界。  相似文献   

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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.  相似文献   

13.
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.  相似文献   

14.
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.  相似文献   

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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  相似文献   

17.
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.  相似文献   

18.
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].  相似文献   

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