单C~*-代数α-比较性的一种等价刻画

给出C~*-代数α-比较性的等价刻画:对于单的含单位元的稳定有限的C~*-代数A而言,A具有α-比较性,当且仅当对于任意的a,b∈W(A),若α·d_r(a)d_τ(b)(_τ∈QT(A)),则a≤b在Cuntz半群W(A)中成立.利用此刻画,证明了具有α-比较性的C~*-代数一定具有弱比较性;若A具有α-比较性,其中α=m+1,则A具有正元的强迹m-比较性;对于满足Kirchberg-R?rdam条件的C~*-代数,E-稳定、严格比较、α-比较性(α=m+1)、强迹m-比较性、弱比较性以及局部弱比较性彼此等价;若α:=inf{α′∈(1,∞)|A具有α′-比较}∞,则A具有α-比较性.     

非单C~*-代数α-比较性的等价刻画

给出非单C~*-代数α-比较性的等价刻画:当每个τ∈QT(■H)均为忠实时,■具有α-比较性,当且仅当对于任意的〈a〉,〈b〉∈Cu(■)且∝,若α·d_τ(a)≤在Cu(■)中成立;一般地,当QT(■H)≠Φ时,■具有α-比较性,当且仅当对于任意的,∈Cu(■),若存在η>0,使得d_τ(α)≤(α~(-1)-η)d_τ(b)(_τ∈QT(■H)),则≤在Cu(■)中成立.     

*-双单型A半群(英文)

一个逆半群如果只有一个D-类,则称为双单逆半群.一个型A半群只有一个D*-类和一个正则D-类,则称为*-双单型A半群.本文采用McAlister的刻画双单逆半群的方法([Proc.London Math.Soc.,1974,28(2):193-221]),用一致半格和可消幺半群建立了*-双单型A半群的结构.     

(AF)实C~*-代数的等价定义

本文给出了有限维实Ｃ~*-代数复化中标准矩阵单位基的描述,继而给出了（ＡＦ）实Ｃ~*-代数的等价定义．     

C_0-半群拓扑(I)

利用有界线性算子半群,引入了一新的局部凸向量拓扑,并对其基本性质进行了讨论.     

C0-半群拓扑(Ⅰ)

利用有界线性算子半群,引入了一新的局部凸向量拓扑,并对其基本性质进行了讨论.     

N(2,2,0)代数的E-反演半群

本文研究了N(2,2,0)代数(S,*,△,0)的E-反演半群.利用N(2,2,0)代数的幂等元,弱逆元,中间单位元的性质和同宇关系,得到了N(2,2,0)代数的半群(S,*)构成E-反演半群的条件及元素α的右伴随非零零因子唯一,且为α的弱逆元等结论,这些结果进一步刻画了N(2,2,0)代数的结构.     

拟对角扩张Cuntz半群的某些性质

设O→J→A→B→O是一个拟对角扩张.作者证明如果J和B具有Cuntz半群的某些性质,则A也具有相同的半群性质.     

半群半直积的主投影性质(英文)

本文研究了半群半直积的主投影性质.利用适当半群,获得了右主投影半群半直积的充分和必要条件,推广了半直积的一些结果.     

全正则子半群构成链的正则半群(英文)

本文考虑全正则子半群构成链的正则半群,得到了正则半群具有全正则子半群构成链的一个充分必要条件,这推广了Jones关于具有全正则子半群构成链的逆半群的结果.特别地,建立了具有全正则子半群构成链的完全0-单半群的结构.     

Certain Cuntz Semigroup Properties of Certain Crossed Product C*-algebras

We show that the following properties of the C^*-algebras in a class Ω are inherited by simple unital C-algebras in the class TAΩ:(1)(m,n)-decomposable,(2) weakly(m,n)-divisible,(3) weak Riesz interpolation.As an application,let A be an infinite dimensional simple unital C-algebra such that A has one of the above-listed properties.Suppose that α:G→Aut(A) is an action of a finite group G on A which has the tracial Rokhlin property.Then the crossed product C^*-algebra C^*(G,A,α) also has the property under consideration.     

On geometric structure of generalized projections in C~*-algebras

Let H be a Hilbert space and A ■ B(H) be a C~*-subalgebra. This paper is devoted to studying the set gP of generalized projections in A from a differential geometric point of view, and mainly focuses on geodesic curves. We prove that the space gP is a C~∞ Banach submanifold of A, and a homogeneous reductive space under the action of Banach Lie group U_A of A. Moreover, we compute the geodesics of gP in a standard fashion, and prove that any generalized projection in a prescribed neighbourhood of p∈gP can be joined with p by a unique geodesic curve in gP.     

Classification Theory for Inductive Limit C^＊-algebras

This paper is a survey on the recent work of the authors and their col-laborators on the Classification of Inductive Limit C*-algebras. Some examples are presented to explain several important ideas.     

Complete Positivity of Elementary Operators on C^＊—algebras

1.IntroductionandPreliminariesInthispaper,AdenotesaC'-algebra.AnelementaryoperatoronAisamappingoftheformE:x-Zaixbi,whereaiandbiarefixedelementsofA.AnidempotenteinAiscalledi-lminimal,ifeAe=Ce.ThesocleofA,soc(A)isdefinedtobethetwo-sidedidealgeneratedbyallminimalidempotentsinAoroiftherearenone.AissaidtObeprimeifxAy=Oimpliesx=oory=oforallx,yinA.Aiscalledprimitiveifithasafaithfulirreduciblerepresenta-tion.LetAandBbeC'-algebras,alinearmap@:A-Biscalledpositiveifdi(a)ispositiveforallPositiv…     

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.     

Spectral Invariant Subalgebras of Reduced Groupoid C~*-algebras

We introduce the notion of property(RD) for a locally compact, Hausdorff and r-discrete groupoid G, and show that the set S_2~l(G) of rapidly decreasing functions on G with respect to a continuous length function l is a dense spectral invariant and Fréchet *-subalgebra of the reduced groupoid C~*-algebra C_r~*(G) of G when G has property(RD) with respect to l, so the K-theories of both algebras are isomorphic under inclusion. Each normalized cocycle c on G, together with an invariant probability measure on the unit space G~0 of G, gives rise to a canonical map τ_c on the algebra C_c(G) of complex continuous functions with compact support on G. We show that the map τ_c can be extended continuously to S_2~l(G) and plays the same role as an n-trace on C_r~*(G) when G has property(RD) and c is of polynomial growth with respect to l, so the Connes' fundament paring between the K-theory and the cyclic cohomology gives us the K-theory invariants on C_r~*(G).     

AF C~*-代数上的Schur积与完全有界映射

证明了ＡＦＣ-代数Ｂ上的有界Ｄ-模映射是完全有界的,这里Ｄ是Ｂ的一个ＳＶｍａｓａ．     

On triangular subalgebras of groupoidC*-algebras

Let ℬ be an AFC*-algebra with Stratila-Voiculescu masaD and letU be a maximal triangular subalgebra of ℬ with diagonalD. Peters, Poon and Wagner showed thatU need not be aC*-subdiagonal subalgebra of ℬ in the sense of Kawamura and Tomiyama. We investigate and explain this phenomena here from the perspective of groupoidC*-algebras by representing257-7 as the “incidence algebra” associated with a topological partial order. A number of examples are given showing what can keep a maximal triangular algebra from beingC*-subdiagonal. Supported by a grant from the National Science Foundation.