GO-空间乘积的子空间仿紧性的充分必要条件

我们知道,GO-空间乘积的子空间不一定仿紧.在2000年,数学家N.Kemoto,K.Tamano和Y.Yajima证明了两个特殊的GO-空间-序数乘积子空间的仿紧性的一个充分必要条件.把这个定理进行了推广,到了两个一般的GO-空间乘积的任意子空间仿紧性的一个充分必要条件.     

GO-空间乘积的子空间的正交紧性

证明了 GO-空间子空间的正交紧性和弱子正交紧性是等价的 .     

正则不可数基数反映GO-空间的性质

本文对“每一个GO-空间都是可数仿紧的”这一性质进行了推广,得到了“每一个GO-空间都是1:x∈［LX-X］}仿紧的”；论证了在一定条件下，一个拓扑空间和一个GO-空间乘积的正规性与这个拓扑空间和一个正则不可数基数的乘积正规性是等价的;并在这两个结论的基础上，又得出了一些重要的定理.     

GO-空间乘积的子空间

数学家 N.Kemoto,T.Nogura,K.D.Sm ith和 Y .Yajim a 1996年证明了两个序数乘积的子空间的正规性、集体正规性、收缩性是等价的 .本文把这个命题进行了推广 ,得到了两个 GO -空间乘积的任意子空间的正规性、集体正规性、收缩性是等价的 .     

GO-空间乘积正规性的充要条件

本文得到了任意两个GO-空间乘积正规性的一个充要条件.     

不可数多个GO-空间乘积的k-仿紧性

证明了不可数多个GO-空间的乘积是k-仿紧空间(相似文献   

几乎概率度量空间(Ⅱ)

本文是作者文[1]的继续.该文中证明了 APM 空间的完备性与诱导一致结构的完备性等价;乘积 APM 空间是完备的当且仅当每个坐标空间是完备的;APM 空间是 m- 紧的当且仅当它是紧的;APM 空间的概率预紧性与诱导一致结构的预紧性等价;概率预紧的 APM 空间的诱导一致拓扑具有基数≤m 的基;m-紧的 APM 空间是 m-几乎可度量化;每个 t- 范数都连续的 APM 空间是可以完备扩张的。     

乘积柔拓扑空间及其性质

先定义了柔集的笛卡尔积,射影序同态,柔拓扑空间的基、子基等概念,在此基础上定义了乘积柔拓扑空间,给出了秉积柔拓扑空间的等价描述以及乘积柔拓扑空间的一些基本性质,证明了一族满足T0分离性(resp.,T1分离性,T2分离性,正则分离性,连通性)的柔拓扑空间的乘积柔拓扑空间仍然满足这种性质,同时证明了第二可数是(ξ)0-可秉性质.     

自旋系统的随机单调性与正相关性

本文讨论乘积空间■{0,1,…,N_u}上的自旋系统,得到了系统随机单调的充要条件,并用“两点测度”的方法给出了系统正相关的一个必要条件.特别地,证明了{0,1}~s空间上自旋系统随机单调与正相关的等价性.     

高斯测度空间上的拟线性变换与高斯变换

我们证明了从具有高斯测度的Banach空间到任意Banach空间中的两类可测变换的等价性。一类是拟线性变换,它保持平移拟不变性及对称不变性,另一类可测变换是高斯交换,它要求变换在定义域及值域的乘积空间上导出的测度是高斯测度。     

Affiliated subspaces and infiniteness of von Neumann algebras

We show that the structural properties of von Neumann algebra s are connected with the metric and order theoretic properties of various classes of affiliated subspaces. Among others we show that properly infinite von Neumann algebra s always admit an affiliated subspace for which (1) closed and orthogonally closed affiliated subspaces are different; (2) splitting and quasi‐splitting affiliated subspaces do not coincide. We provide an involved construction showing that concepts of splitting and quasi‐splitting subspaces are non‐equivalent in any GNS representation space arising from a faithful normal state on a Type I factor. We are putting together the theory of quasi‐splitting subspaces developed for inner product spaces on one side and the modular theory of von Neumann algebra s on the other side.     

Reducing Subspaces of Toeplitz Operators on Nψ-type Quotient Modules on the Torus

In this paper, we prove that the Toeplitz operator with finite Blaschke product symbol Sψ(z) on Nψhas at least m non-trivial minimal reducing subspaces, of Sψ(z) on any of these minimal reducing subspaces is unitary equivalent to the Bergman shift Mz.     

Sobolev圆盘代数的不变子空间

研究了Sobolev圆盘代数R(D)上乘自变量算子M_z的不变子空间,给出了M_z在任何不变子空间上限制的基本性质,证明了M_z分别限制在两个不变子空间上酉等价当且仅当这两个不变子空间相等,并描述了M_z的一类公共零点在边界的不变子空间的结构.     

On the product of projectors and generalized inverses

We consider generalized inverses of linear operators on arbitrary vector spaces and study the question when their product in reverse order is again a generalized inverse. This problem is equivalent to the question when the product of two projectors is again a projector, and we discuss necessary and sufficient conditions in terms of their kernels and images alone. We give a new representation of the product of generalized inverses that does not require explicit knowledge of the factors. Our approach is based on implicit representations of subspaces via their orthogonals in the dual space. For Fredholm operators, the corresponding computations reduce to finite-dimensional problems. We illustrate our results with examples for matrices and linear ordinary boundary problems.     

Analytic Hilbert Spaces over the Complex Plane

In this paper, we study the structure of quasi-invariant subspaces of analytic Hilbert spaces over the complex plane. We especially investigate when two quasi-invariant subspaces are similar or unitarily equivalent for an analytic Hilbert space over the complex plane.