Diagonal Invariant Ideals of Topologically Graded C~*-algebras

We study diagonal invariant ideals of topologically graded C*-algebras over discrete groups. Since all Toeplitz algebras defined on discrete groups are topologically graded, the results in this paper have improved the first author's previous works on this topic.

面向软件定义的C~4ISR系统资源建模方法研究

为实现马赛克化的C~4ISR系统构建模式,瞄准系统“元要素”构建,以软件定义技术为驱动,探讨了可定义的资源建模原理,提出了资源建模过程,定义了C~4ISR系统资源概念内涵,基于多视角建立了资源分类框架;围绕资源信息流受控和能力开放共享,提出了模型要素,针对7类资源特点建立了参考模型。通过典型案例下资源实例化建模,验证了模型对软件定义的系统构建的适用性。

Proof of inseparable prime C~*-algebras A with RR(A)=0 being primitive C~*-algebras

First, that prime C~* -algebras with countable primitive ideals are all primitive C*-algebras is proved. Then the proof that prime C~* -algebras with property RR(A) = 0 are all primitive C~*-algebras is given.

Classification of Homomorphisms from C(X)to Simple C~*-Algebras of Real Rank Zero

Let A be a unital simple C-algebra of real rank zero,stable rank one,with weakly unperforated K0（A）and unique normalized quasi-trace τ,and let X be a compact metric space.We show that two monomorphisms Φ,Ψ:C（X）→A are approximately unitarily equivalent if and only if Φ and Ψ induce the same element in KL（C（X）,A）and the two linear functionals τ ο Φ and τ ο Φ are equal.We also show that,with an injectivity condition,an almost multiplicative morphism from C（X） into A with vanishing KK-obstacle is close to a homomorphism.

Homomorphisms between JC~*-algebras and Lie C(?)-algebras

It is shown that every almost ＊-homomorphism h ： A→B of a unital JC＊-algebra A to a unital JC＊-algebra B is a ＊-homomorphism when h（rx） = rh（x） （r 〉 1） for all x∈A, and that every almost linear mapping h ： A→B is a ＊-homomorphism when h（2^nu o y） - h（2^nu） o h（y）, h（3^nu o y） - h（3^nu） o h（y） or h（q^nu o y） = h（q^nu） o h（y） for all unitaries u ∈A, all y ∈A, and n = 0, 1,.... Here the numbers 2, 3, q depend on the functional equations given in the almost linear mappings. We prove that every almost ＊-homomorphism h ： A→B of a unital Lie C＊-algebra A to a unital Lie C＊-algebra B is a ＊-homomorphism when h（rx） = rh（x） （r 〉 1） for all x ∈A.

Approximately Linear Mappings in Banach Modules over a C~*-algebra

Let X and Y be vector spaces. The authors show that a mapping f ： X →Y satisfies the functional equation 2d f（∑^2d j=1（-1）^j＋1xj/2d）=∑^2dj=1（-1）^j＋1f（xj） with f（0） = 0 if and only if the mapping f ： X→ Y is Cauchy additive, and prove the stability of the functional equation （≠） in Banach modules over a unital C^＊-algebra, and in Poisson Banach modules over a unital Poisson C＊-algebra. Let A and B be unital C^＊-algebras, Poisson C^＊-algebras or Poisson JC^＊- algebras. As an application, the authors show that every almost homomorphism h ： A →B of A into is a homomorphism when h（（2d-1）^nuy） =- h（（2d-1）^nu）h（y） or h（（2d-1）^nuoy） = h（（2d-1）^nu）oh（y） for all unitaries u ∈A, all y ∈ A, n = 0, 1, 2,.... Moreover, the authors prove the stability of homomorphisms in C^＊-algebras, Poisson C^＊-algebras or Poisson JC^＊-algebras.

Pairing and Quantum Double of Finite Hopf C~*-Algebras

This paper defines a pairing of two finite Hopf C^＊-algebras A and B, and investigates the interactions between them. If the pairing is non-degenerate, then the quantum double construction is given. This construction yields a new finite Hopf C^＊-algebra D（A, B）. The canonical embedding maps of A and B into the double are both isometric.

Property T^(**) for C~*-algebras

Extending the notion of property T of finite von Neumann algebras to general yon Neu- mann algebras, we define and study in this paper property T＊＊ for （possibly non-unital） C＊-algebras. We obtain several results of property T＊＊ parallel to those of property T for unital C＊-algebras. Moreover, we show that a discrete group F has property T if and only if the group C＊-algebra C＊（F） （or equivalently, the reduced group C＊-algebra C＊（F）） has property T＊＊. We also show that the compact operators K（g2） has property T＊＊ but co does not have property T＊＊.

The α-comparison Property and Finite Nuclear Dimension of Generalized Inductive Limits for C~*-algebras

The paper is devoted to the study of generalized inductive limit of C＊-algebras with coherent maps being completely positive contractions of order zero： the nuclear dimension of generalized inductive limit of C＊-algebras with finite nuclear dimension is finite; the generalized inductive limits of C＊-algebras with the α-comparison property also have the s-comparison property.

Irreducible * Representations of Real C~*-Algebras

In this paper,we show that a topologically irreducible * representation of a real C~*- algebra is also algebraically irreducible.Moreover,the properties of pure real states on a real C~*- algebra and their left kernels are discussed.

A C~*-ALGEBRA APPROACHTO THE IRREDUCIBILITY OFCOWEN-DOUGLAS OPERATORS

The authors consider the irreducibility of the Cowen-Douglas operator T. It is proved that T is irreducible iff the unital C*-algebra generated by some non-zero blocks in the decomposition of T with respect to (Ker Tn+1 Ker Tn) is M.(C).

Notes on the Mapping Torus of C~*-Algebra

Let （A, Z, α） be a C*-dynamical system, and αn=id （n is a fixed positive integer）. A natural problem is how the C*-crossed product A ×αZ relates to A×αZn. The answer is the following: A×αZ≌MA×αZn,where MA×αZn is the mapping torus of , and （A×αZn, n, ）is the dual system

C~*-代数上的非负矩阵与正定矩阵

研究C*-代数上矩阵的非负性、可逆性与正定性，应用分块矩阵的技巧，得到了非负矩阵的一系列判别法。同时，研究了矩阵可逆性的判定问题，在此基础上给出了正定矩阵的判别方法．

拟对角扩张C~*-代数的性质

0→J→A→B→0是一个拟对角扩张.证明以下结论:(1)如果J和B具有弱可比性质,则A也具有弱可比性质;(2)如果J和B具有强消去性质,则A也具有强消去性质;(3)如果J和B具有n-无孔性质,则A也具有n-无孔性质.

纯无限单C~*-代数的扩张代数的K-理论Ⅱ

给出了有单位元的纯无限单的C^＊一代数A通过Κ的扩张代数E的K-理论的一种刻画．证明了K0（E）同构于E中所有具有无限余投影的无限投影的Murry—von Neumann等价类全体所成的交换群，它还同构于上述投影的同伦等价类或酉等价类全体所成的交换群．还证明了对扩张代数E中的任一满的正元a，存在元索x∈E，使得x^＊ax=1，其中Κ为可分无限维Hilbert空间上紧算子全体所成的C^＊-代数．

C~*-代数迹极限性质的封闭性(英文)

在迹极限的意义下，特别是在单代数的条件下，研究某些C^＊-代数性质的封闭性，假设A=（t2）lim n→∞（An,pn）,An上至少有一个迹态或An具有（SP）性质，则A也有相同的结果；假设A=（t3）lim n→∞（An,pn）并且A中单代数，如果TR（An）=0,tsr（An）=1和An具有投影消去律，则A也有相同的结果。

C~*代数上保持不定正交性的线性映射

设A和B是含单位元的C~*代数,s∈A和t∈B是可逆自伴元,对任意的x∈A及z∈B,定义x^+=s^(-1)x~*s,z^+=t^(-1)z~*t。假定A是实秩零的并且Φ:A→B是有界线性满射。证明了对任意的 都成立的充要条件是Φ(1)可逆,Φ(1)^+Φ(1)=Φ(1)Φ(1)^+∈Z(B)(B的中心),并且存在从A到B上的满+同态Ψ,使得对所有的x∈A都有Φ(x)=Φ(1)Ψ(x)成立。对于一般C~*代数上保正交性的线性映射Φ,在假定Φ(1)可逆的条件下,也得到类似的结果。

不可分素C^k-代数与本原C~*-代数的讨论

本文证明了：若Ａ是不可分的素Ｃ＊－代数，且包含非０的Ｌｉｍｉｎａｌ遗传Ｃ＊－子代数，则Ａ是本原Ｃ＊－代数．

矩阵C~*代数上的群作用与*-同构(英文)

通过矩阵 C*代数上的不变群作用 ,给出了决定

关于一族C~*代数的表示

利用关于完全正映射的Stinespring膨胀定理,给出了两个C*代数之间的表示定理,以及一族C*代数表示到同一个Hilbert空间上的表示.