C(X)A上的自同构群

本文研究了连续函数代数C（X）与某个C*-代数A的张量积C（X）A的自同构群．当A是有单位元且具有平凡中心的C*-代数时,本文完全刻划了C（X）A的自同构群．利用AF-代数的K-理论,本文还刻划了当X是全不连通的紧致Hausdorff空间时,C（X）与紧算子理想的张量积的自同构群．     

对偶扩张代数的Frobenius态射和固定点代数

设A是由箭图Q和关系I所确定的代数,D(A)是代数A的对偶扩张代数, 对应的箭图Q*和关系I*由Q和I决定．本文证明:带关系箭图(Q*,I*)的自同构由带关系箭图(Q,I)的自同构决定;D(A)的Frobenius态射由A的Frobenius态射完全决定;代数D(A)的固定点代数同构于相应的代数A的固定点代数与A°P的固定点代数的张量积,特别地,当Q为单的箭图时,代数D(A)的固定点代数同构于代数A的固定点代数的对偶扩张代数．     

关于连续迹C~*-代数间映射的谱

本文引进了连续迹C*-代数间映射的谱,并证明了其是C*-代数谱空间的 闭子集进而给出了刻划.同时,我们得到了诸如下半连续性等类似于形如C(X)Mn C*-代数间映射的谱性质.     

迹稳定秩一的C~*-代数

本文引入了一类迹稳定秩一的C*-代数,证明了迹稳定秩一的C*-代数与AF-代数的张量积是迹稳定秩一的,得到了一个可分的单的有单位元的迹稳定秩一的,并且具有SP性质的C*-代数是稳定秩一的.同时,还讨论了迹稳定秩一的C*-代数的K-群的某些性质.     

AF C*-代数上的映射

本文讨论AF C*-代数中的一些映射的线性性质和它们的局部性质之间的关系,研究AFC*-代数A上的保持乘法的局部自同构φ在A中矩阵单位系上的作用,证明了φ是A上的自同构.对于UHF代数上满等距的结构,还证明了UHF代数上的2-局部(满线性)等距是线性的.     

一类基于量子环面非交换结合代数的模

在量子环面[1]上构造一类非交换结合代数AQ-模M(a,b),我们还刻划了AQ-模的结构并揭示[2]一类商模序列:每个商模Mn(a)/Mn+1(a)都同构于M(a,0),每个商模的自同构群AutMn(a)/Mn+1(a)均与C*同构.     

C~*标准代数中效应的序列同构

主要借助于C~*标准算子代数中的有限秩算子对一般的效应元进行刻画.证明了C~*标准算子代数A的效应代数E(A)上的每个序列自同构和自同构ψ都具有形式ψ(A)=UAU~*,其中A∈E(A),U为酉算子或反酉算子.     

纯无限单C*-代数的扩张代数的K-理论

给出了纯无限单的C*-代数A通过K的扩张代数E的K-理论的一种刻划.证明了K0(E)等于E中所有无限投影的Murry-von Neumann等价类所成的交换群,K1(E)等于E中酉元的同伦等价类所成的交换群.作为一个应用,最后给出了A中酉元可提升的等价条件,其中K为可分无限维Hilbert空间上紧箅子全体所成的C*-代数.     

I(k)中迹极限C*-代数的注记

给出了I(k)中迹极限C*-代数的某些性质.特别地给出了I(k)中迹极限c*-代数的的几个等价定义.利用此结果,证明了如果A是单的有单位元的C*-代数,并且A具有唯一的标准迹,A=(t4)Lim n→∞ (An,pn),其中An∈I(k),则A=(t4) lim n→∞(An,pn),其中An∈I(O).最后给出了I(k)中迹极限C*-代数的Ko-群的消去律性质.     

Cartan型李代数的自同构群

本文证明了素特征域 Ｆ上广义 Ｃａｒｔａｎ型李代数的自同构群都是 ＡｕｔＷ（ｍ,ｎ）的子群．文中对于除幂代数相应的可容许自同构给出了刻划,从而对广义 Ｃａｒｔａｎ型李代数的自同构给出了刻划     

IDEAL STRUCTURE IN CENTAIN C^*-TENSOR PRODUCTS

This paper discusses the ideal structure in tensor product $A\bigotimes B$ of C^*-algebra A and B,and introduces the concept of property (I) and property (K) with respect to the problem.When A is an AF(or scattered) C^*-algebra,it is shown that for any C^*-algebra B,the ideals in $A\bigotimes B$ can be expressed by those of A and B.     

Product Systems of C*-correspondences and Baaj—Skandalis Duality

Acta Mathematica Sinica, English Series - Let X = {Xp}]p∈P be a product system over a lattice ordered group (G, P) with coefficients in a C*-algebra $${\cal A}$$ . In this paper, we study the...     

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.     

Duality for Convex Monoids

Every C*-algebra gives rise to an effect module and a convex space of states, which are connected via Kadison duality. We explore this duality in several examples, where the C*-algebra is equipped with the structure of a finite-dimensional Hopf algebra. When the Hopf algebra is the function algebra or group algebra of a finite group, the resulting state spaces form convex monoids. We will prove that both these convex monoids can be obtained from the other one by taking a coproduct of density matrices on the irreducible representations. We will also show that the same holds for a tensor product of a group and a function algebra.     

Asymptotic representations of the reduced C*-algebra of a free group: an example

We give an example of a non-trivial asymptotic representationof the reduced C*-algebra of a free group. This example allowsus to evaluate the asymptotic tensor C*-norm of some elementsin tensor product C*-algebras and to show semi-invertibilityof the non-invertible extension of C*_r(₂) considered by Haagerupand Thorbjørnsen.     

Continuous Bundles of C*-Algebras with Discontinuous Tensor Products

For each non-exact C*-algebra A and infinite compact Hausdorffspace X there exists a continuous bundle B of C*-algebras onX such that the minimal tensor product bundle AB is discontinuous.The bundle B can be chosen to be unital with constant simplefibre. When X is metrizable, B can also be chosen to be separable.As a corollary, a C*-algebra A is exact if and only if A Bis continuous for all unital continuous C*-bundles B on a giveninfinite compact Hausdorff base space. The key to proving theseresults is showing that for a non-exact C*-algebra A there existsa separable unital continuous C*-bundle B on [0,1] such thatA B is continuous on [0,1] and discontinuous at 1, a counter-intuitiveresult. For a non-exact C*-algebra A and separable C*-bundleB on [0,1], the set of points of discontinuity of A B in [0,1]can be of positive Lebesgue measure, and even of measure 1.2000 Mathematics Subject Classification 46L06 (primary), 46L35(secondary).     

C*-bialgebra Defined as the Direct Sum of UHF Algebras

Let 𝒜₀(*) denote the direct sum of a certain set of uniformly hyperfinite (UHF) algebras, and let 𝒜(*) ≡ C ⊕ 𝒜₀(*). We introduce a non-cocommutative comultiplication Δ_? on 𝒜(*), and give an example of comodule-C*-algebra of the C*-bialgebra (𝒜(*), Δ_?). With respect to Δ_?, we define a nonsymmetric tensor product of *-representations of UHF algebras and show tensor product formulas of Gel'fand–Na\u?mark–Segal (GNS) representations by product states.     

Characterization of compact quantum group

Given a C^＊-algebra A and a comultiplication Ф on A, we show that the pair （A, Ф） is a compact quantum group if and only if the associated multiplier Hopf ^＊-algebra （A, ФA） is a compact Hopf ^＊-algebra.     

Chain conditions for C*-algebras coming from Hilbert C*-modules

In this paper we define and study chain conditions for Hilbert C*-modules through their C*-algebras of compact operators and discuss their perseverance under Morita equivalence and tensor products. We show that these chain conditions are passed from the C*-algebra to its Hilbert module under certain conditions. We also study chain conditions for Hilbert modules coming from inclusion of C*-algebra with a faithful conditional expectation.