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1.
Assume X is a normed space,every x * ∈ S(X*) can reach its norm at some point in B(X),and Y is a β-normed space.If there is a quotient space of Y which is asymptotically isometric to l β,then L(X,Y) contains an asymptotically isometric copy of l β.Some sufficient conditions are given under which L(X,Y) fails to have the fixed point property for nonexpansive mappings on closed bounded β-convex subsets of L(X,Y).  相似文献   

2.
Zip模(英文)     
张翠萍  陈建龙 《东北数学》2008,24(3):233-249
A ring R is called right zip provided that if the annihilator τR(X) of a subset X of R is zero, then τR(Y) = 0 for some finite subset Y C X. Such rings have been studied in literature. For a right R-module M, we introduce the notion of a zip module, which is a generalization of the right zip ring. A number of properties of this sort of modules are established, and the equivalent conditions of the right zip ring R are given. Moreover, the zip properties of matrices and polynomials over a module M are studied.  相似文献   

3.
借助于矩阵对的标准相关分解,导出了极限limλ→0X(λI+YAX)^-1Y存在的充分必要条件,在极限存在的情况下,给出了极限的表达式,并讨论了结果的一些应用.  相似文献   

4.
且引言考虑线性互补问题**P(q,M):求X二(X;,x。,…,x。厂E”使得x>O,训x)E*x+g>o,/U(X)一O(1)其中M一(m;。)为nXn矩阵(不必对称),q一切,q。,…,q。)rER“为给定常向量.通常情况下已有求解LCP(q,M)的若干著名算法[‘-’j.本文提出求解LCP(q,M)的一种新算法一行作用法,方法具有如下特点:(i)每次迭代只需n个简单的投影运算,每次投影只涉及矩阵M的一行;(n)生成新的迭代点x‘“‘时只利用前次迭代点/;(iii)对矩阵M不实施任何整体运算.因而适合于求解大型(巨型)稀疏问题,且…  相似文献   

5.
章前 《应用数学》1998,11(4):49-52
考虑带约束奇异线性模型Y=Xβ+ε,Lβ=0,E(ε)=0,cov(ε)=σ~2V,其中V为非负定矩阵,X为任意秩.文章研究了观察向量Y的线性变换对回归系数条件可估函数Sβ的G-M估计的影响,并将条件可估子空间μ(X'L')划分成Ω+Ω_+Ω_2.当μ(S')Ω时,Sβ的条件G-M估计在模型变化后其优良性不变;当μ(S')Ω_1时,模型变化后Sβ仍可估,但Sβ的条件G-M估计的方差要变大;当μ(S')Ω_2时,Sβ不可估.  相似文献   

6.
设(X,d1,f1∞)与(Y ,d2,g1,∞)为两个非自治动力系统,h是从(X,d1,f.∞)到(Y,d2,g1∞)的拓扑半共轭.通过对自治动力系统中的h一极小覆盖的研究,本文得到了以下结论:1)对于任意的Y∈Y及X∈h-1(y),orb(x,f1∞)被h映射为orb(y,g1∞),w(x,f1∞)被h映射为w(y,g1∞);2)在(X,d1,f1∞)中引入关于拓扑半共轭的h-极小覆盖的定义,证明了h一极小覆盖的存在性;3)对于任意的XEX和Y∈Y,在(w(z,f1∞),f1∞。(x,f1,∞)与(w(y,g∞),g1,∞(y,g1∞))均构成原系统的子系统的前提下,R(f1∞)被h映射为R(g1∞).这些结论丰富了非自治动力系统的内容.  相似文献   

7.
龙泊廷 《数学通讯》2011,(11):35-36
已知圆的直径的两个端点分别为M(x1,Y1),N(x2,Y2),设点P(x,y)是该圆上的任意一点,则Mp=(z—zl,Y—Y1),N--P:=(z—X2,Y—Y2).  相似文献   

8.
Let X, Y be real or complex Banach spaces with dimension greater than 2 and A, B be standard operator algebras on X and Y, respectively. Let φ :A →B be a unital surjective map. In this paper, we characterize the map φ on .4 which satisfies (A - B)R = R(A-B) ξR ((A-B)→ (φ(B))φ(R) =φ(R)((A)- (B)) for A, B, R E .4 and for some scalar  相似文献   

9.
Let X and Y be vector spaces. The authors show that a mapping f : X →Y satisfies the functional equation 2d f(∑^2d j=1(-1)^j+1xj/2d)=∑^2dj=1(-1)^j+1f(xj) with f(0) = 0 if and only if the mapping f : X→ Y is Cauchy additive, and prove the stability of the functional equation (≠) in Banach modules over a unital C^*-algebra, and in Poisson Banach modules over a unital Poisson C*-algebra. Let A and B be unital C^*-algebras, Poisson C^*-algebras or Poisson JC^*- algebras. As an application, the authors show that every almost homomorphism h : A →B of A into is a homomorphism when h((2d-1)^nuy) =- h((2d-1)^nu)h(y) or h((2d-1)^nuoy) = h((2d-1)^nu)oh(y) for all unitaries u ∈A, all y ∈ A, n = 0, 1, 2,.... Moreover, the authors prove the stability of homomorphisms in C^*-algebras, Poisson C^*-algebras or Poisson JC^*-algebras.  相似文献   

10.
设R为非负交换整半环,用M_n(R)表示R上所有n×n矩阵构成的矩阵半环.令T是M_n(R)到其自身的线性变换,若T满足|T(X)|~+=|X|~+,■X∈M_n(R)(或|T(X)|~-=|X|~-,(?)X∈Mn(R)),称T为M_n(R)上保持正行列式(负行列式)的线性变换.刻画了n≥4时,M_n(R)上保持正行列式/负行列式的线性满射形式.  相似文献   

11.
Let (M, g) be an n-dimensional Riemannian manifold and T*M be its cotan-gent bundle equipped with the rescaled Sasaki type metric. In this paper, we firstly study the paraholomorphy property of the rescaled Sasaki type metric by using some compati-ble paracomplex structures on T*M. Second, we construct locally decomposable Golden Riemannian structures on T*M . Finally we investigate curvature properties of T*M .  相似文献   

12.
m阶中立型泛函差分方程的振动性准则   总被引:3,自引:0,他引:3  
程金发  Annie Z 《数学学报》2002,45(6):1207-121
本文了研究m阶混合型中立泛函差分方程:△m(xn+cxn-h+c*xn+h*)=k(qxn-g+Pxn+g*),k=±1.这里C,C*,p,q是实数,且h,h*,g和g*是正整数,并且对于上述方程建立了一些新的振动性准则.本文结果改进了文[1]中的所有定理,并回答了由 Grace S.R.提出的一个公开问题.  相似文献   

13.
Let A be a standard operator algebra on a Banach space of dimension 〉 1 and B be an arbitrary algebra over Q the field of rational numbers. Suppose that M : A → B and M^* : B → A are surjective maps such that {M(r(aM^*(x)+M^*(x)a))=r(M(a)x+xM(a)), M^*(r(M(a)x+xM(a)))=r(aM^*(x)+M^*(x)a) for all a ∈ A, x ∈ B, where r is a fixed nonzero rational number. Then both M and M^* are additive.  相似文献   

14.
本文讨论强度为随机变量X,应力为复合x2-更新过程Y(t)的半随机过程可靠性模型的结构可靠度一致估计问题.获得在设计基准期[0,T]内结构可靠度表达式和结构可靠度的一致估计.  相似文献   

15.
在流行病学,生物统计学和天文学中常遇到随机截断数据.在随机截断下,人们关心的随机变量X被另一个随机变量Y干扰.只有当X≥Y时,才能观测到X和Y.在这个模型下,人们需要用截断数据估计X的分布函数F.本文证明,F的非参数最大似然估计Fn在下述意义下服从中心极限定理.对任何可测函数g(x),n~(1/2)∫g(x)[dFn(x)-dF(x)]依分布收敛到均值为零方差为σ2的正态分布.从这个结果可以得出F的各种矩,特征函数等估计的渐近正态性.作为推论,还可以得到Fn在整个直线上的依分布收敛.我们的结果不要求X和Y的分布函数连续,得到的方差公式是简明的.  相似文献   

16.
为方便起见,本文约定:连点A是国数y一人X)的图象上的任一点,通过某种蛮操,点*'出在囫数y一人X)的图象上,则称点A和历*'是因数y一八X)的国象上的两个"相关杰".苦点A是国数y一/(X)的图象上的任一点,通过某种变换点*'在团数y一g(X)的图象上,则称东A租点{是因数y一人工)和囹数y一g(X)的国象上的两个"相关内".教学中,我们发现:有许多留地颤手的有关函数问题,都可以通过构造"相关点"的方法加以解决,通过教学的后息反馈,效果自好.现不自截拙,和盘托出,愿自百位同行共同交流.1求凸数值_-___。。。、ZX+…  相似文献   

17.
对于每个诺特半完全代数A上的模M,都有一个谱序列E_(pq)~*(M)与之相对应.本文证明了有限生成A-模M是拟Koszul的当且仅当谱序列E_(pq)~*(M)的第E~2层是平凡的.与之对偶,本文叙述了余拟Koszul模情况下的类似结果.  相似文献   

18.
Obstruction Theory and Coincidences in Positive Codimension   总被引:1,自引:0,他引:1  
Let f, g : X→Y be two maps between closed manifolds with dim X ≥ dim Y = n ≥ 3. We study the primary obstruction on(f, g) to deforming f and g to be coincidence free on the n-th skeleton of X. We give examples for which obstructions to deforming f and g to be coincidence free are detected by on (f, g).  相似文献   

19.
Jian Yong  WANG 《数学学报(英文版)》2009,25(10):1729-1740
For 0 〈β 〈 1, the author once wrote a paper to deal with the representation problem of the conjugate cone [L^β[0, 1]β^* of complex β-nanach space L^β[0, 1]. In this paper, replacing [0, 1] with a Borel finite measure space (Ω,M,μ) and replacing the complex field C with a Banach space X, we study the representation problem of the conjugate cone [L^β(μ, X)]β^* of L^β(μ, X), and obtain [L^β(μ, X)]β^*≌L^∞ M^+(μ, S), called the Quasi-Representation Theorem of [L^β(μ, X)]β^*.  相似文献   

20.
S-Zip模     
引进S-zip模的概念.设R是一个具有单位元的任意环,M是一个右R-模,S=End_R(M).称一个右R-模M是S-zip模,如果对于M的任一非空子集X,由X在S中的左零化子l_S(X)=0可以推出存在一个有限子集Y(■)X,使得l_S(Y)=0.给出了S-zip模的一些刻画,讨论了S-zip模与相关模之间的关系,并且将zip环的一些已知结论拓广到S-zip模上.  相似文献   

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