有界线性算子的性质(gy)

定义了四种新的谱性质:性质(y),性质(gy),性质(by),性质(gby),从而再次推广了Weyl型定理,并探讨了这四种新性质同Weyl型定理及其推广性质之间的关系.     

T-S-Ferrers性质与区间序指标

集中于T-S-Ferrers性质指标以及与之相关的区间序指标的研究。首先给出T-S-Ferrers性质指标的性质,包括T-S-Ferrers性质指标的等价形式、T-S-Ferrers性质指标与S-强完全指标的关系以及大偏好关系与严格偏好关系的T-S-Ferrers性质指标之间关系。然后定义区间序指标,并讨论区间序指标的性质以及T-S-Ferrers性质与区间序指标之间的关系。     

圆锥曲线的一个性质

圆锥曲线的一个性质朱传汇（湖北民族学院数学系４４５０００）圆锥曲线的经典性质（如焦点准线性质、光学性质）已为人们所熟知，对其他性质（如中点弦性质）的讨论仍是热门话题之一．在对圆锥曲线的内接多边形的研究中，笔者发现如下有趣的性质．定理对于圆锥曲线Ｃ上任...     

关于d-跟踪性质的一些注记

d-和d-跟踪性质是Dastjerdi和Hosseini为推广伪轨跟踪性质于2010年提出的.本文考察该动力性质在迭代系统和逆极限系统下的性质.首先证明对动力系统(X,f),以下三命题等价:(1)f具有d-跟踪性质(d-跟踪性质);(2)对任意k∈N,f~k也具有d-跟踪性质(d-跟踪性质);(3)存在k∈N,使得f~k具有d-跟踪性质(d-跟踪性质).进而证明具有d-跟踪性质的系统是链混合的.最后得到对于由{X_i,φ_i,f_i)_(i=1)~∞生成的逆极限系统(X_∞,f_∞),若每个f_i均具有d-跟踪性质(或者,d-跟踪性质,遍历跟踪性),则诱导映射f_∞也具有d-跟踪性质(相应地,d-跟踪性质,遍历跟踪性).     

Banach空间的p-弱近似性质

给出了Banach空间的p-弱近似性质和p-有界弱近似性质的定义,获得了这些性质的一些刻画.利用这些刻画证明了如果一个Banach空间X的对偶空间X~*有p-弱近似性质(或p-有界弱近似性质),则X有p-弱近似性质(或p-有界弱近似性质),在一般情况下反之不成立.     

关于相对紧性质的研究

利用有限交性质的集族及网的性质描述了相对紧性质,给出了相对紧性质的两个等价结果.     

（S）性质和局部接近一致光滑空间

本文证明了（Ｓ）性质的一个特征．进而证明了（Ｓ）性质和ＬＮＵＳ是等价的．研究了（Ｓ）性质和（Ｈ＊）性质，Ｈａｄｅｃ性质之间的关系．     

用设k法解决与三个等比分式相关竞赛题的两个层次

<正>同学们在学习代数的有关性质时,不仅需要知道该性质是什么,如何应用,还需要知道该性质是如何推导的．因为明白了性质的推导过程,才会更加清楚如何运用该性质解决相关问题．比如,我们知道等比性质的内容:     

Morita Context环的若干性质

研究由Morita Contexts所确定的环,讨论它的K-好环性质,弱Semicom-mutative性质,有许多单式正则元性质和广义稳定环性质等.     

CFI算子和Weyl型定理(英文)

广义(ω)性质是Weyl定理的一种变形,它推广了由Rakocevic在[Matematicki Vesnik,1985,37(4):423-426]中引入的(ω)性质.本文利用一致Fredholm算子指标性质(CFT),给出了Hilbert空间上的有界线性算子满足广义(ω)性质的充要条件.另外还利用这一性质考虑了广义(ω_1)性质和(ω_1)性质的等价性.     

Property (ω1) and Single Valued Extension Property

In this note we study the property (ω1),a variant of Weyl's theorem by means of the single valued extension property,and establish for a bounded linear operator defined on a Banach space the necessary and sufficient condition for which property (ω1) holds.As a consequence of the main result,the stability of property (ω1) is discussed.     

The Phillips properties

A Banach space has the Phillips property if the canonical projection is sequentially weak-norm continuous, and has the weak Phillips property if is sequentially weak-weak continuous. We study both properties in connection with other geometric properties, such as the Dunford-Pettis property, Pelczynski's properties and (V), and the Schur property.

     

Quantifying properties (K) and (μs$\mu ^{s}$)

A Banach space X has property (K), whenever every weak* null sequence in the dual space admits a convex block subsequence ${(f_n)}_{n=1}^{\infty }$ so that $⟨f_n,x_n⟩\to 0$ as $n\to \infty$ for every weakly null sequence ${(x_n)}_{n=1}^{\infty }$ in X; X has property $({\mu }^s)$ if every weak* null sequence in $X^{\ast }$ admits a subsequence so that all of its subsequences are Cesàro convergent to 0 with respect to the Mackey topology. Both property $({\mu }^s)$ and reflexivity (or even the Grothendieck property) imply property (K). In this paper, we propose natural ways for quantifying the aforementioned properties in the spirit of recent results concerning other familiar properties of Banach spaces.     

Strong CHIP, normality, and linear regularity of convex sets

We extend the property (N) introduced by Jameson for closed convex cones to the normal property for a finite collection of convex sets in a Hilbert space. Variations of the normal property, such as the weak normal property and the uniform normal property, are also introduced. A dual form of the normal property is derived. When applied to closed convex cones, the dual normal property is the property (G) introduced by Jameson. Normality of convex sets provides a new perspective on the relationship between the strong conical hull intersection property (strong CHIP) and various regularity properties. In particular, we prove that the weak normal property is a dual characterization of the strong CHIP, and the uniform normal property is a characterization of the linear regularity. Moreover, the linear regularity is equivalent to the fact that the normality constant for feasible direction cones of the convex sets at is bounded away from 0 uniformly over all points in the intersection of these convex sets.

     

性质(u)在序列空间ces_p(E_n)中的提升

主要研究了性质(u)从Banach空间En到序列空间cesp(En)的提升问题.     

The single-valued extension property for sums and products of commuting operators

It is shown that the sum and the product of two commuting Banach space operators with Dunford's property (C) have the single-valued extension property.     

On the notion of relative property (T) for inclusions of von Neumann algebras

We prove that the notion of rigidity (or relative property (T)) for inclusions of finite von Neumann algebras recently defined by the second author is equivalent to a weaker property, in which no “continuity constants” are required. The proof is by contradiction and uses infinite products of completely positive maps, regarded as correspondences.     

Property (ωˊ) and Its Perturbation

In this note we define the property (ωˊ),a variant of Weyl's theorem,and establish for a bounded linear operator defined on a Hilbert space the necessary and sufficient conditions for which property (ωˊ) holds by means of the variant of the essential approximate point spectrum σ1(.) and the spectrum defined in view of the property of consistency in Fredholm and index.In addition,the perturbation of property (ωˊ) is discussed.     

The Equivalence between Property (ω) and Weyl’s Theorem

We call T ∈ B(H) consistent in Fredholm and index (briefly a CFI operator) if for each B ∈ B(H),T B and BT are Fredholm together and the same index of B,or not Fredholm together.Using a new spectrum defined in view of the CFI operator,we give the equivalence of Weyl’s theorem and property (ω) for T and its conjugate operator T* .In addition,the property (ω) for operator matrices is considered.     

Signal recovery under mutual incoherence property and oracle inequalities

We consider the signal recovery through an unconstrained minimization in the framework of mutual incoherence property. A sufficient condition is provided to guarantee the stable recovery in the noisy case. Furthermore, oracle inequalities of both sparse signals and non-sparse signals are derived under the mutual incoherence condition in the case of Gaussian noises. Finally, we investigate the relationship between mutual incoherence property and robust null space property and find that robust null space property can be deduced from the mutual incoherence property.