分离向量与自反性

设A是B(X)的子代数,且A具有分离向量x0,本文讨论它的2-自反性和亚自反性,并就具有分离向量的交换算子代数.部分地回答了J.A.Deddens在文献[7]中提出的一些关于自反性的问题.     

自反代数的环自同构和环反自同构

设A为Banach空间X中一自反代数使得在LatA中O ≠0且X_≠X,则A的每一环自同构￠（环反自同构φ）具有形式￠（A）=TAT^-1(φ（A）=TA^*T^-1),其中T：X→X（T：X^*→X）或为一有界线性双射算子或为一有界共轭线性性双射算子。特别地,￠和φ都是连续的。     

算子代数的斜积

引入了算子代数的一种新运算"斜积",证明了在这个新定义的斜积运算下算子代数的自反性保持不变.研究发现,斜积运算对应的子空间格是拓扑意义下的格的直积关系.这个新发现的重要意义在于由此可从已知的自反子空间格生成更多更复杂的新自反格,从而得到新的自反代数.在此基础上,本文对KS-代数保持性等其他非自伴代数类的性质也作了相应研究.     

自反Banach空间上算子代数的超自反性

本文引入自发Banach空间上算子代数A的超自反定义，讨论了A超自反的充要条件，超自反常数的估计以及超自反在代数同构下的不变性。     

算子代数的C_σ性质、C_σ性质与自反性

本文首次引入算子集合的Ｃ＿σ性质和性质的概念，它们与性质Ｃ和性质Ｄ＿σ（１）有一定的关系．两个主要结果是：（１）具有性质Ｃ＿σ的对偶代数一定是遗传自反的．（２）如果对偶代数所生成的ｎ－自反代数具有性质Ｃ＿σ，则该对偶代数一定是遗传ｎ－自反的．     

自反算子代数的环自同构

设A是Banach空间X上的自反算子代数,并且A的不变子空间格Lat A满足0+≠0和X_≠X,αA→A是环自同构.如果X是实空间,并且dim X±＞1,则存在X上的线性有界可逆算子A,使得α(T)=ATA-1,T∈A;如果X是复空间,并且dim X±=∞,则α(T)=ATA-1,T∈A.其中AX→X是线性、或者共轭线性有界可逆算子.     

算子代数的Cσ性质,C↑～σ性质与自反性

本文首次引入算子集合的Ｃσ性质和Ｃ↑～σ性质的概念，它们与性质Ｃ和性质Ｄσ（１）有一定的关系：两个主要结果是：（１）具有性质Ｃ↑～σ的对偶代数一定是遗传自反的。（２）如果对偶代数所生成的ｎ－自反代数具有性质Ｃσ，则该对偶代数一定是遗传ｎ－自反的。     

自反代数的双局部导子

证明了自反Banach空间X中自反代数A到B(x)的导子集合是拓扑代数双自反的.     

关于超自反算子代数

本文讨论了超自反算子代数的等价条件及超自反性在张量积、直和、同构、约化中的不变性，改进加深了孙善利＾［２］的结果，并证明了两类Ｖｏｎ Ｎｅｕｍａｎｎ代数的超自反性。     

幂等算子乘积的群逆的表示

正1引言设X为Banach空间,B(X)表示Banach空间X上有界线性算子的全体.设A∈B(X),则满足方程ABA=A的有界线性算子B∈B(X)称为A的{1}-逆,记作A~-;满足方程ABA=A,BAB=B的有界线性算子B∈B(X)称为A的自反广义逆或A的{1,2}-逆,通常记作A~+.若B∈B(X)满足下列方程     

Strictly nilpotent elements and bispectral operators in the Weyl algebra

In this paper we give another characterization of the strictly nilpotent elements in the Weyl algebra, which (apart from the polynomials) turn out to be all bispectral operators with polynomial coefficients. This also allows to reformulate in terms of bispectral operators the famous conjecture, that all the endomorphisms of the Weyl algebra are automorphisms (Dixmier, Kirillov, etc).     

Algebra of Bergman Operators with Automorphic Coefficients and Parabolic Group of Shifts

We study the algebra of operators with the Bergman kernel extended by isometric weighted shift operators. The coefficients of the algebra are assumed to be automorphic with respect to a cyclic parabolic group of fractional-linear transformations of a unit disk and continuous on the Riemann surface of the group. By using an isometric transformation, we obtain a quasiautomorphic matrix operator on the Riemann surface with properties similar to the properties of the Bergman operator. This enables us to construct the algebra of symbols, devise an efficient criterion for the Fredholm property, and calculate the index of the operators of the algebra considered.     

管范畴上的算子及其应用

本文定义了管范畴上的一些算子,研究了它们的一些性质,给出了循环单列代数的Ringel-Hall代数H(T)的结构常数FML,N的一个计算公式．利用这些算子和这个公式,我们得到了其合成代数C(T)及半单模[l(?)i=1nSi](t∈Z+)在H(T)中的一些中心化子．事实上,它们是H(T)的中心元素,且是H(T)在其合成代数C(T)上代数无关的生成元．     

Remarks on reductive operator algebras

It is shown that a weakly closed operator algebra with the property that each of its invariant subspaces is reducing and which is either strictly cyclic or has only closed invariant linear manifolds, must be a von Neumann algebra.     

Operator algebras with strictly cyclic vectors

We obtain results concerning the invariant subspaces of strictly cyclic operator algebras. In particular, we show that transitivity of a strictly cyclic algebra implies its strict (and hence even its strong) density.Translated from Matematicheskie Zametki, Vol. 16, No. 2, pp. 253–257, August, 1974.     

The preservation of Sahlqvist equations in completions of Boolean algebras with operators

Monk [1970] extended the notion of the completion of a Boolean algebra to Boolean algebras with operators. Under the assumption that the operators of such an algebra are completely additive, he showed that the completion of always exists and is unique up to isomorphisms over . Moreover, strictly positive equations are preserved under completions a strictly positive equation that holds in must hold in the completion of . In this paper we extend Monk’s preservation theorem by proving that certain kinds of Sahlqvist equations (as well as some other types of equations and implications) are preserved under completions. An example is given that shows that arbitrary Sahlqvist equations need not be preserved. Received May 3, 1998; accepted in final form October 7, 1998.     

Equivalence after extension and Schur coupling coincide for inessential operators

In recent years the coincidence of the operator relations equivalence after extension (EAE) and Schur coupling (SC) was settled for the Hilbert space case. For Banach space operators, it is known that SC implies EAE, but the converse implication is only known for special classes of operators, such as Fredholm operators with index zero and operators that can in norm be approximated by invertible operators. In this paper we prove that the implication EAE $?$ SC also holds for inessential Banach space operators. The inessential operators were introduced as a generalization of the compact operators, and include, besides the compact operators, also the strictly singular and strictly co-singular operators; in fact they form the largest ideal such that the invertible elements in the associated quotient algebra coincide with (the equivalence classes of) the Fredholm operators.     

Triangular strictly cyclic operators

The title refers to an empty class of operators. Moreover, if T is a triangular Banach space operator, then either T is algebraic and the double commutant has infinite strict multiplicity, or T is not algebraic and the commutant has infinite strict multiplicity. A rationally strictly cyclic, but not strictly cyclic, operator cannot have finite strict multiplicity.This research was partially supported by a Grant of the National Science Foundation.     

Hochschild and Cyclic Homology of Ore Extensions and Some Examples of Quantum Algebras

For every Ore extension we construct a chain complex giving its Hochschild homology. As an application we compute the Hochschild and cyclic homology of an arbitrary multiparametric affine space and the Hochschild homology of the algebra of differential operators over this space, in the generic case.     

Cyclic cohomology of Hopf algebras of transverse symmetries in codimension 1

We develop intrinsic tools for computing the periodic Hopf cyclic cohomology of Hopf algebras related to transverse symmetry in codimension 1. Besides the Hopf algebra found by Connes and the first author in their work on the local index formula for transversely hypoelliptic operators on foliations, this family includes its ‘Schwarzian’ quotient, on which the Rankin-Cohen universal deformation formula is based, the extended Connes-Kreimer Hopf algebra related to renormalization of divergences in QFT, as well as a series of cyclic coverings of these Hopf algebras, motivated by the treatment of transverse symmetry for non-orientable foliations.The method for calculating their Hopf cyclic cohomology is based on two computational devices, which work in tandem and complement each other: one is a spectral sequence for bicrossed product Hopf algebras and the other a Cartan-type homotopy formula in Hopf cyclic cohomology.