BMO空间中f与f_N的范数比较

ＢＭＯ空间中ｆ与ｆ_Ｎ的范数比较刘为铨（安徽芜湖师专）设ｆ（ｘ）为定义于Ｒ上的局部可积函数，Ｑ为Ｒ中的任一立方体。｜Ｑ｜为Ｑ的Ｌｅｂｅｓｅｕｅ测度，ｆ（Ｘ）在Ｑ上的平均值记作若ｆ（Ｘ）满足条件则称人工）为有界平均振动函数，一切有界平均振动函数所构成的?..     

gr－正则环和矩阵环的gr－正则性

本文主要证明了（１）当Ｇ是有限群时，Ｇ－型分次环Ｒ是ｇｒ－正则的当且仅当ＲＧ是正则的当且仅当Ｍ＿Ｇ（Ｒ）是ｇｒ－正则的当且仅当对每个和Ｇ的任意非空子集Ｈ和Ｆ，Ｍ＿（ＨＸＦ）（Ｒ）的每个矩阵都有１－逆。（２）当Ｇ是任意群，Ｇ－型分次环只是反ｇｒ－正则的当且仅当Ｆ是反正则的当且仅当对每个和Ｇ的任意作非空子集Ｈ和Ｋ，ＦＭ＿（Ｈ×Ｆ）（Ｒ）的每个矩阵有２－逆当且仅当ＦＭ＿Ｇ（Ｒ）是ｇｒ－反正则的。     

S-闭空间的测度(Ⅱ)(英文)

继续讨论了Ｓ－闭空间的测度．首先得到了：当Ｘ是Ｓ－闭空间，则Ｃ（Ｘ）上的对偶空间与Ｘ上有界Ｆ－Ｓ测度一致；同时给出∫ｆｄｕ＝０的充要条件     

S—闭空间的测度（II）

继续讨论了Ｓ－闭空间的测度。首先得到了：当Ｘ是Ｓ－闭空间，则Ｃ（Ｘ）上的对偶空间与Ｘ上有界Ｆ－Ｓ测度一致；同时给出∫ｆｄｕ＝０的充要条件。     

关于G－Matlis自反模的几点注记

本文证明，如果Ｒ是一个Ｎｏｅｔｈｅｒ完备半局部环，则Ｒ－模Ｍ是Ｎｏｅｔｈｅｒ（Ａｒｔｉｎ）模当且仅当对任意ＡｒｔｉｎＲ－模Ｎ，是Ａｒｔｉｎ（Ｎｏｅｔｈｅｒ）模．     

关于调和映照的一个Liouville型定理

令Ｍ、Ｎ是完备Ｒｉｅｍａｎｎ流形,设Ｍ上不存在任何非平凡的有界调和函数,Ｎ的截面曲具有上界其为ｋ＞０·设ｕ：Ｍ→Ｎ是一个调和映照且ｕ（Ｍ）ＢＲ（Ｐ）,其中Ｒ＝·如果ＢＲ（Ｐ）位于 Ｐ的割迹之内,并且ｕ（Ｍ）∩ＢＲ（Ｐ）最多只有一个点,则ｕ必是一个常值映照．     

半群上的非交换调和分析

设Ａ（Ｍ）是 Ｃ＊－代数（ｖｏｎ Ｎｅｕｍａｎｎ代数）．本文证明了，若φ是定义在Ｒ＋上取值于Ａ（Ｍ）的范数连续的有界正定函数，则φ可表示为Ｒ＋上取值于Ａ＇＇（Ｍ）的有界半变差向量测度的Ｌａｐｌａｃｅ变换．同时也证明了取值于Ａ（Ｍ）的Ｈａｍｂｕｒｇｅｒ型的矩量问题．     

完备格上的上拓扑和区间拓扑

对完备格 Ｌ;记ｖ（Ｌ）为 Ｌ上的上拓扑之闭集格本文证明了完备格 Ｌ为 Ｆ－分配格当且仅当映射ｓｕｐ：ｖ（Ｌ）→Ｌ为满完备格同态;若Ｌ为Ｆ－分配的Ｂｏｏｌｅ格,则Ｌ同构于某幂集格、对Ｔ１格 Ｌ,证明了下述各条件等价。（１） Ｌ同构于某幂集格;（２） Ｌ上的区间拓扑是 Ｈａｕｓｄｏｒｆｆ的;（３）是有限分离的;（４） Ｌ是连续的对马空间（Ｘ,Ｏ（Ｘ））,进一步证明了 Ｏ（Ｘ）上的区间拓扑不可能为 Ｈａｕｓｄｏｒｆｆ的,除非（Ｘ, Ｏ（Ｘ））是离散空间．     

单边Hardy－Littlewood极大算子的加权弱（1．1）型不等式

设Ｍ￣＋、Ｍ￣－为单边Ｈａｒｄｙ－Ｌｉｔｔｌｅｗｏｏｄ极大算子，ｕ（ｘ）、ｖ（ｘ）为实直线Ｒ上两个权函数。本文得到Ｍ￣＋（或Ｍ￣－）关于测度ｖ（ｘ）ｄｘ和ｕ（ｘ）ｄｘ是弱（１．１）型的当且仅当（ｕ，ｖ）∈或（ｕ，ｖ）．     

REMARKS ON QUASI-PERFECT RINGS AND FC-RINGS

设Ｒ是有单位元的环，Ｓ是Ｒ的几乎优越扩张，Ｇ是有限群且｜Ｇ｜－１∈Ｒ．证明了Ｒ是ＦＣ－环（拟完备环，凝聚环）当且仅当Ｓ是ＦＣ－环（拟完备环，凝聚环），也当且仅当Ｓｍａｃｈ积Ｒ＃Ｇ＊是ＦＣ－环（拟完备环，凝聚环）．     

On the existence of complete Kähler metrics of negative Riemannian curvature bounded away from zero on ellipsoidal domains inC n

Summary The purpose of this paper is to prove that every ellipsoidal domain in Cⁿ admits a complete Kähler metric whose Riemannian sectional curvature is bounded from above by a negative constant (Theorem 1). We construct a Kähler metric, in a natural way, as potential of a suitable function defining the boundary (§2). Directly we compute the curvature tensor and we find upper and lower bounds for the holomorphic sectional curvature (§ 4, § 5). In order to prove the boundness of Riemannian sectional curvature we use finally a classical pinching argument (§ 6). We also obtain that for certain ellipsoidal domains the curvature tensor is very strongly negative in the sense of [15] (§ 3). Finally we prove that the metric constructed on ellipsoidal domains in Cⁿ is the Bergman metric if and only if the domain is biholomorphic to the ball (Theorem 2). In [8], [9] R. E. Greene and S. G. Krantz gave large families of examples of complete Kähler manifolds with Riemannian sectional curvature bounded from above by a negative constant; they are sufficiently small deformations of the ball in Cⁿ, with the Bergman metric. Before the only known example of complete simply-connected Kähler manifold with Riemannian sectional curvature upper bounded by a negative constant, not biholomorphic to the ball, was the surface constructed by G. D. Mostow and Y. T. Siu in [14], to the best of the author's knowledge, is not known at present if this example is biholomorphic to a domain in Cⁿ.     

The connectivity and approximative properties of sets in linear normed spaces

The connectivity of suns is investigated. It is shown that a sun is connected in finite-dimensional space. A set M in uniformly convex space X is shown to be approximatively compact if and only if M is P-compact and the metric projection of X onto M is upper semicontinuous.     

An Analog of Titchmarsh’s Theorem for the Fourier–Walsh Transform

The space clos(X) of all nonempty closed subsets of an unbounded metric space X is considered. The space clos(X) is endowed with a metric in which a sequence of closed sets converges if and only if the distances from these sets to a fixed point θ are bounded and, for any r, the sequence of the unions of the given sets with the exterior balls of radius r centered at θ converges in the Hausdorff metric. The metric on clos(X) thus defined is not equivalent to the Hausdorff metric, whatever the initial metric space X. Conditions for a set to be closed, totally bounded, or compact in clos(X) are obtained; criteria for the bounded compactness and separability of clos(X) are given. The space of continuous maps from a compact space to clos(X) is considered; conditions for a set to be totally bounded in this space are found.     

Ponomarev-系中的紧覆盖映射

本文讨论了Ponomarev-系中的紧覆盖映射与集族之间的关系,得到如下结果.(1)对于Ponomarev-系(f,M,x,{P_n}),f是紧覆盖映射当且仅当每一P_n具有CFP-性.(2)对于Ponomarev-系(f,M,X,P),f是紧覆盖映射当且仅当P是X的强k-网.作为这些结果的一些应用,本文分别给出了度量空间紧覆盖π-象和度量空间紧覆盖象的内部结构.     

Noncompact manifolds with nonnegative Ricci curvature

Let (M, d) be a metric space. For 0 < r < R, let G(p, r, R) be the group obtained by considering all loops based at a point p ∈ M whose image is contained in the closed ball of radius r and identifying two loops if there is a homotopy between them that is contained in the open ball of radius R. In this article we study the asymptotic behavior of the G(p, r, R) groups of complete open manifolds of nonnegative Ricci curvature. We also find relationships between the G(p, r, R) groups and tangent cones at infinity of a metric space and show that any tangent cone at infinity of a complete open manifold of nonnegative Ricci curvature and small linear diameter growth is its own universal cover.     

TVS-锥度量空间中的统计收敛

本文研究TVS-锥度量空间中的统计收敛以及TVS-锥度量空间的统计完备性.令（X，E，P，d）表示一个TVS-锥度量空间.利用定义在有序Hausdorff拓扑向量空间E上的Minkowski函数ρ，证明了在X上存在一个通常意义下的度量d_ρ，使得X中的序列（x_n）在锥度量d意义下统计收敛到x ∈ X，当且仅当（x_n）在度量d_ρ意义下统计收敛到x.基于此，我们证明了任意一个TVS-锥统计Cauchy序列是几乎处处TVS-锥Cauchy序列，还证明了任意一个TVS-锥统计收敛的序列是几乎处处TVS-锥收敛的.从而，TVS-锥度量空间（X，d）是d-完备的，当且仅当它是d-统计完备的.基于以上结论，通常度量空间中统计收敛的许多性质都可以平行地推广到锥度量空间中统计收敛的情形.     

Ideals in the Roe Algebras of Discrete Metric Spaces with Coefficients in B(H)

The notion of an ideal family of weighted subspaces of a discrete metric space X with bounded geometry is introduced.It is shown that,if X has Yu's property A,the ideal structure of the Roe algebra of X with coefficients in B(H) is completely characterized by the ideal families of weighted subspaces of X,where B(H) denotes the C*-algebra of bounded linear operators on a separable Hilbert space H.     

Metric spaces in synthetic topology

We investigate the relationship between the synthetic approach to topology, in which every set is equipped with an intrinsic topology, and constructive theory of metric spaces. We relate the synthetic notion of compactness of Cantor space to Brouwer’s Fan Principle. We show that the intrinsic and metric topologies of complete separable metric spaces coincide if they do so for Baire space. In Russian Constructivism the match between synthetic and metric topology breaks down, as even a very simple complete totally bounded space fails to be compact, and its topology is strictly finer than the metric topology. In contrast, in Brouwer’s intuitionism synthetic and metric notions of topology and compactness agree.     

The Szeg? Metric Associated to Hardy Spaces of Clifford Algebra Valued Functions and Some Geometric Properties

In analogy to complex function theory we introduce a Szeg? metric in the context of hypercomplex function theory dealing with functions that take values in a Clifford algebra. In particular, we are dealing with Clifford algebra valued functions that are annihilated by the Euclidean Dirac operator in \mathbbR^m+1{\mathbb{R}^{m+1}} . These are often called monogenic functions. As a consequence of the isometry between two Hardy spaces of monogenic functions on domains that are related to each other by a conformal map, the generalized Szeg? metric turns out to have a pseudo-invariance under M?bius transformations. This property is crucially applied to show that the curvature of this metric is always negative on bounded domains. Furthermore, it allows us to establish that this metric is complete on bounded domains.     

函数空间上的Cauchy收敛拓扑(英文)

本文研究了度量空间X到实直线R上的连续函数空间C(X,R)上的Cauchy收敛拓扑Tc.u,点态收敛拓扑Tp.u,紧开拓扑Tk和一致收敛拓扑Tu相等的等价条件.利用Cauchy覆盖得到了(C(X,R),Tc.u)的特征与X的Cauchy覆盖数相等的一个对偶定理,获得了(C(X,R),Tc.u)可度量化当且仅当(C(X,R),Tc.u)是第一可数的当且仅当X具有可数Cauchy覆盖数,肯定地回答了Michael H Clapp等在文献[1]中提到的问题.