线性空间中的共逼近

本文研究了在局部凸空间和赋范线性空间中的（f-）共逼近和强（f-）共逼近的一些性质,给出了f-共逼近、强f-共逼近和强f-Kolmogorov集的特征定理.并举例说明G.S.Rao的两主要定理是不正确的,同时作了相应的更正.所得的结果中的部分推广和改进了Song、Rao和Narang等人的相应结果.     

点传递线性空间

本文是关于点传递线性空间的一个分类工作. 设${\mathcal{S}}$是一个点数为51的正则线性空间,其线长为6, $G$ 是${\cal S}$的一个自同构群.本文证明了群$G$不可能点传递.     

Stability Constants for Courant Approximations

We study stability constants for Courant approximations in the metric of the spaces L₂()and W ₂ ¹ () in classes of triangular grids with uniformly bounded angles and with angles approaching zero. In the first case, we give sufficiently precise numerical estimates for the constants, and in the second case, we give asymptotics of the behavior of the boundaries for the corresponding quadratic forms.     

Finite Linear Spaces II

Batten and Beutelspacher have characterized Finite Linear Spaces with lines of size n,n + 1 and n + 2, and with v (n + 1)²for n 22, and some of the cases for smaller n. In this article, using the structuredapproach we presented in our earlier article [8], we complete this characterization for smalln.     

关于仿射线性相关性的探讨

在线性空间中引入了仿射线性相关的概念,给出了它的特征刻画及若干重要性质,并用仿射线性相关性刻画了非齐线性方程组解的结构。     

Exact Values of Some Geometric Constants of Orlicz Spaces

We present the exact values of nonsquare constants, von Neumann-Jordan constants, Jung constants, packing constants, weakly convergent sequence coefficients and normal structure coefficients in a class of reflexive Orlicz function spaces and sequence spaces equipped with Luxemburg norm and Orlicz norm.     

Banach空间中的Jordan-von Neumann型常数和正规结构

首先利用James常数J(X)给出了Jordan-von Neumann型常数C_(-∞)(X)的一个估计式,然后由此式说明确实存在C_(-∞)(X)C_Z(X)的例子,最后利用C_(-∞)(X)和Benavides常数R(a,X)的关系,得到了空间具有正规结构的充分条件,并通过一些例子说明我们的结论严格推广了一些文献中的结果.     

Linear Isometries of S~p Spaces

Abstract This paper gencralizes the result about linear isometries of S~ spaces given by W.P.Novingerand D.M.Oberlin[2]for the unite dise of C to the bounded symmetric domains of C~n     

Banach空间中线性斜积半流指数稳定性的Holder型刻画

为了在Banach空间X的对偶空间上刻画线性斜演化半流的一致指数稳定性,借助泛函分析与算子理论得到了其一致指数稳定的一些H?lder型充要条件,所得结果推广了稳定性理论中的一些已有结论.     

Linear Isometries of S^D Spaces

This paper generalizes the result about linear isometries of S^pspaces given by W.P.Novinger and D.M.Oberlin[2] for the unite dise of C to the bounded symmetrie domains of C^n。     

平移空间的线性结构

本文证明了在平移空间上可利用距离在一定条件下构作出线性结构,引入了次范整线性空间的概念,还证明了平移空间是次范整线性空间当且仅当它的平移群是Abel群.泛函分析学中的有界线性算子定理,Hahn-Banach定理以及共鸣定理都可以移植于次范整线性空间之中.     

赋范线性空间中的Hilbert型积分不等式

基于利用一个积分恒等式的新技巧,建立了赋范线性空间中新的Hilbert型积分不等式.这些新的结果包含了n维欧氏空间中n重积分的Hilbert型积分不等式作为其特殊情形.     

Type,Cotype Constants and Clarkson's Inequalities for Banach Spaces

It is shown that a Banach space satisfies Clarkson's inequalities if and only if its “type or cotype constant” is 1, which implies in particular that the notions of G_o - and G_n - Fourier type by Milman [16] are equivalent. A sequence of related results is also given.     

Banach 空间中von Neumann-Jordan 型常数的一些性质

该文主要给出von Neumann-Jordan型常数的一些性质. 首先得到利用von Neumann-Jordan型常数来刻划一致非 方的等价条件. 其次介绍了von Neumann-Jordan型常数与正规结构的关系. 最后介绍了C_1'(X)与其他空间常数之间的关系, 例如C_1'(X)与C₁(X)之间的关系等等.     

Linear Independence of q-Analogues of Certain Classical Constants

Let K be ? or an imaginary quadratic number field, and q ∈ K an integer with ¦q¦ > 1. We give a quantitative version of Σ_n≥1 a_n/(qⁿ ? 1) ? K for non-zero periodic sequences (a_n) in K of period length ≤ 2. As a corollary, we get a quantitative version of the linear independence over K of 1, the q-harmonic series, and a q-analogue of log 2. A similar result on 1, the q-harmonic series, and a q-analogue of ζ(2) is also proved. Mathematics Subject Classification (2000): 11J72, 11J82     

Best Interpolatory Approximation in Normed Linear Spaces

A theory of best approximation with interpolatory contraints from a finite-dimensional subspaceMof a normed linear spaceXis developed. In particular, to eachxX, best approximations are sought from a subsetM(x) ofMwhichdependson the elementxbeing approximated. It is shown that this “parametric approximation” problem can be essentially reduced to the “usual” one involving a certainfixedsubspaceM₀ofM. More detailed results can be obtained when (1) Xis a Hilbert space, or (2) Mis an “interpolating subspace” ofX(in the sense of [1]).     

Stability of Derivations in Modular Spaces

In this paper, we present a fixed point method to prove generalized Hyers–Ulam stability of derivations in modular spaces.