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1.
本文讨论了超空间2x的某些局部覆盖性质,并给出下面二个结果:定理1设X是T2空间,则2x紧当且仅当2x是局部meta-Lindelof空间.定理21设X是T1空间,则2xm-紧当且仅当2x是局部m-紧。  相似文献   

2.
讨论了Lasnev空间的超空间的某些性质.文中构造一反例,证明存在可数Lasnev空间,其紧子集超空间不是层型空间.并指出文[6]中关于上述结果的证明中有一关键性失误,故[6]中的反例尚不能说明上述结论成立.本文还对具有σ-CF拟基的k′空间给出一个刻画定理  相似文献   

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文献[1]中定义了序列紧fts(每个不分明集序列有收敛的子序列)和可数紧fts(每个可数开覆盖存在有限子覆盖)。对于序列紧fts,得到“每个fts都是序列紧的”病态结果,由此可见这样定义的序列紧fts不是一般拓扑学中序列紧的良扩张。对于可数紧fts,[2]在评论F-紧性时,论证了凡T_1空间都不是F-紧空间,以上的论证也可得到凡T_1空间都不是可数紧fts的病态结果。我们还要指出,[1]定义的可数紧fts也不是一般拓扑学中可数紧的良扩张。  相似文献   

4.
设(X,τ)是一个拓扑空间。在本文中,我们证明了在超空间2X上局部有限拓扑eτ与局部有限覆盖拟一致uLF所导出的超拓扑|2uLF|是相同的。我们还证明了下面条件是等价的:(1)(X,τ)是仿紧的;(2)(X,τ)是orth紧的,且eτ=|2uFT|;(3)存在一个Lebes-yue拟一致uL,使eτ<  相似文献   

5.
球覆盖性质不是同胚不变的   总被引:2,自引:0,他引:2       下载免费PDF全文
Banach空间$X$中的一个开球族$\ss$是$X$的球覆盖, 如果$B$中的任一元素不包含原点,且$B$中元素之并覆盖了$X$的单位球面$S_{X}$. Banach空间$X$称为具有球覆盖性质,如果$X$有一个由可数多个球组成的球覆盖. 通过在 $l^\infty$上构造等价范数证明了Banach空间$X$的球覆盖性质既不是线性同胚不变的, 也不是在商映射下不变的, 同时, 它也不具有子空间的可继承性.  相似文献   

6.
在L-拓扑空间中定义了L-子集的几乎超紧性,讨论了几乎超紧L-子集的性质以及L-子集的几乎超紧性与超紧性、近似超紧性及几乎良紧性之间的关系,给出了几乎超紧L-子集的网式及滤子刻画并证明了L-拓扑空间的几乎超紧性是几乎紧性的“L-推广”.  相似文献   

7.
在非紧超凸度量空间中建立了一个新的极大元定理.作为应用,获得了连续选择及其不动点定理和一个Browder-Fan不动点定理.最后,新建了非紧超凸度量空间中的定性对策和抽象经济的平衡点存在定理.  相似文献   

8.
文开庭 《数学进展》2005,34(2):208-212
在非紧超凸度量空间中的非紧允许集上,建立了一个新的Browder不动点定理.作为应用,在非紧超凸度量空间中,研究了Ky Fan截口问题和相交问题,并新建了两个Ky Fan重合定理.  相似文献   

9.
林寿  滕辉 《数学进展》1994,23(3):234-237
本文证明了如下两个定理:(1)C_k(X)为强Frechet空间(或者Frechet空间)的充分必要条件是X中的每一开K-覆盖序列{u_n:n∈N},存在U_n∈u_n,使{U_n:n∈N}为X的K-序列,(2)C_k(X)有可数扇密度的充分必要条件是X中的每一开K-覆盖序列{u_n:n∈N}存在u_n的有限于族u'_n,使{u'_n:n∈N}是X的开K-覆盖.  相似文献   

10.
紧开覆盖的一个新的Ky Fan型匹配定理及其应用   总被引:1,自引:0,他引:1  
文开庭 《数学进展》2007,36(4):407-414
建立了紧开覆盖的一个新的Ky Fan型匹配定理.作为应用,研究了Fan-Browder型重合定理、Ky Fan型最佳逼近定理、极大元定理及超凸空间中的定性对策和抽象经济的平衡存在定理.  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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