微分算子Lie代数上的Leibniz 2-上循环

中心扩张问题在Leibniz代数的研究中起着非常重要的作用,因此有许多文章研究各种各样Leibniz代数的中心扩张问题.在这篇文章里,我们确定了微分算子Lie代数上的所有一维Leibniz中心扩张.     

Derivation Simple Color Algebras and Semisimple Lie Color Algebras

Let K be an algebraically closed field of arbitrary characteristic and Γ an abelian multiplicative group equipped with a bicharacter ε: Γ × Γ → K*. It is proved that, for any finite-dimensional derivation simple color algebra A over K, there exists a simple color algebra S and a color vector space V such that A? S? S^ε(V), where S^ε(V) is the ε-symmetric algebra of V. As an application of this result, a necessary and sufficient condition such that a Lie color algebra is semisimple is obtained.     

The Lower Socle and Finite Rank Elementary Operators

Abstract

We define the lower socle of a semiprime algebra 𝒜 as the sum of all minimal left ideals 𝒜e where e is a minimal idempotent such that the division algebra e𝒜e is finite dimensional. We study the connection between the condition that the elements a _k , b _k , 1 ≤ k ≤ n, lie in the lower socle of 𝒜 and the condition that the elementary operator x ? a ₁ xb ₁ + ? + a _n xb _n has finite rank. As an application we obtain some results on derivations certain of whose powers have finite rank.     

包含紧算子理想的Toeplitz算子代数的刻画

设G为一个torsion-free的离散群,（G,G＋）为一个拟序群,记T^G (G)为相应的Toeplitz算子代数,K(l^2(G 1)为l^2(G )上的紧算子全体,本文证明了K(l^2(G ))增包含于T^G (G)当且仅当下列两个条件时满足。（1）（G,G＋）为一个序群,（2）G中存在一个最小的正元。     

Finite Rank Operators in Closed Maximal Triangular Algebras

Ｆｉｎｉｔｅｒａｎｋｏｐｅｒａｔｏｒｓａｎｄｒａｎｋｏｎｅｏｐｅｒａｔｏｒｓａｒｅｉｍｐｏｒｔａｎｔｔｏｔｈｅｔｈｅｏｒｙｏｆｎｅｓｔａｌｇｅｂｒａｓ .Ｉｎａｎｅｓｔａｌｇｅｂｒａ ,ｅａｃｈｆｉｎｉｔｅｒａｎｋｏｐｅｒａｔｏｒｃａｎｂｅｗｒｉｔｔｅｎａｓａｆｉｎｉｔｅｓｕｍｏｆｒａｎｋｏｎｅｏｐｅｒａｔｏｒｓｗｈｉｃｈｂｅｌｏｎｇｔｏｉｔｓｅｌｆ (Ｔｈｉｓｒｅｓｕｌｔｉｓｉｎ [1 ],ｂｕｔｂｅｌｏｎｇｓｔｏＪ .Ｒ .Ｒｉｎｇｒｏｓｅ) .Ｉｎａｎａｔｕｒａｌｗａｙ ,ｗｅｍａｙａｓｋ :　Ｑｕｅｓｔｉｏｎ…     

Lie-Yamaguti代数的相对微分算子

本文研究Lie-Yamaguti代数的相对微分算子.首先给出Lie-Yamaguti代数上相对微分算子的概念并给出等价刻画.随后,引入Lie-Yamaguti代数上相对微分算子的上同调.最后,讨论Lie-Yamaguti代数上相对微分算子的无穷小形变.     

Hom-李-Yamaguti代数上的相对罗巴算子

本文引入Hom-李-Yamaguti代数上相对罗巴算子的概念,并利用Nijenhuis算子和图给出相对罗巴算子的等价刻画.随后,引入Hom-李-Yamaguti代数上相对罗巴算子的上同调理论.最后,利用上同调方法探讨相对罗巴算子的形变.     

Murphy Operators and the Centre of the Iwahori-Hecke Algebras of Type A

In this paper we introduce a family of polynomials indexed by pairs of partitions and show that if these polynomials are self-orthogonal then the centre of the Iwahori-Hecke algebra of the symmetric group is precisely the set of symmetric polynomials in the Murphy operators.     

解析Sobolev型空间上的算子与算子代数

介绍Hardy-Sobolev空间和Fock空间及其算子与算子代数研究方面所做的工作,包括对这两类空间上几类特殊算子有界性、紧性、Fredholm性、指标理论、谱和本性谱、范数和本性范数、Schatten-p类的讨论,以及由它们所生成的C~*-代数的研究.     

Norm Estimates for Multiplication Operators in Hilbert Algebras

In this paper, it is proved that for the bilinear operator defined by the operation of multiplication in an arbitrary associative algebra with unit over the fields or , the infimum of its norms with respect to all scalar products in this algebra (with ) is either infinite or at most . Sufficient conditions for this bound to be not less than are obtained. The finiteness of this bound for infinite-dimensional Grassmann algebras was first proved by Kupsh and Smolyanov (this was used for constructing a functional representation for Fock superalgebras).     

Von Neumann代数中套子代数上的导子(Ⅱ)

本文主要研究因子ＶｏｎＮｅｕｍａｎｎ代数中套子代数上的导子。证明了由因子ＶｏｎＮｅｕｍａａｎ代数中套子代数到紧算子的任何导子都是内导子。     

Classification of 2-Step Nilpotent Lie Algebras of Dimension 8 with 2-Dimensional Center

In this article, by choosing appropriate basis, we give a complete classification of 2-step nilpotent Lie algebras of dimension 8 with 2-dimensional center.     

Constants of Derivation and Differential Ideals

ABSTRACT

Let R be a differential domain finitely generated over a differential field F of characteristic 0. Let C be the subfield of differential constants of F. This paper investigates conditions on differential ideals of R that are necessary or sufficient to guarantee that C is also the set of constants of differentiation of the quotient field, E, of R. In particular, when C is algebraically closed and R has a finite number of height one differential prime ideals, there are no new constants in E. An example where F is infinitely generated over C shows the converse is false. If F is finitely generated over C and R is a polynomial ring over F, sufficient conditions on F are given so that no new constants in E does imply only finitely many height one prime differential ideals in R. In particular, F can be Q¯(T) where T is a finite transcendence set.

     

Centroids of Zinbiel Algebras

Zinbiel algebras were introduced by a way of Koszul dual to Leibniz algebras and connected with commutative associate algebras, pre-Lie algebras and dendriform algebras etc. In this article, the centroids of Zinbiel algebra are discussed. We study the proprieties of centroids and also determinate the centroids of Zinbiel algebras up to dimension ≤4. As consequent, we get the conclusion that the centroids of 2-dimensional Zinbiel algebras are not small and 3,4-dimensional Zinbiel algebras are almost small.     

算子的酉等价与换位代数的K0-群

We show that two irreducible operators on Н are unitarily equivalent if and only if W^*（AФB)‘≌M2(C), and give an answer to the open question posed by J. B. Conway (Subnormal Operators, 7r Pitman, Advanced Publishing Program,Boston, London, Melbourne, 1981) for irreducible operator. We also show that if T, T1 and T2 are irreducible operators with TФT1≌TФT2, then T1≌T2. Finally, we show that K0(A(D))≌Z, giving a new result on the Ko-group of Banach algebras.     

Bijective 1-Cocycles and Classification of 3-Dimensional Left-Symmetric Algebras

Left-symmetric algebras have close relations with many important fields in mathematics and mathematical physics. Their classification is very complicated due to the nonassociativity. In this article, we re-study the correspondence between left-symmetric algebras and the bijective 1-cocycles. Then a procedure is provided to classify left-symmetric algebras in terms of classification of equivalent classes of bijective 1-cocycles. As an example, the 3-dimensional complex left-symmetric algebras are classified.     

Spline Approximation Methods with Uniform Meshes in Algebras of Multiplication and Convolution Operators

The purpose of this paper is to obtain necessary and sufficient conditions for maximum defect spline approximation methods with uniform meshes to be stable. The methods are applied to operators belonging to the closed subalgebra of ℒ︁ (L² (ℝ)) generated by operators of multiplication by piecewise continuous functions on ℝ and convolution operators also with piecewise continuousgenerating functions. To that purpose, a C*-algebra of sequences is introduced, which contains the special sequences of approximating operators we are interested in. There is a direct relationship between the applicability of the approximation method to a given operator and invertibility of the corresponding sequence in this C*-algebra. Exploring this relationship, applicability criteria are derived by the use of C*-algebra and Banach algebra techniques (essentialization, localization andidentification of the local algebras by means of construction of locally equivalent representations). Finally, examples are presented, including explicit conditions for the applicability of spline Galerkin methods to Wiener-Hopf operators with piecewise continuous symbols.     

Toeplitz Operators Associated to Unimodular Algebras

We introduce a class of function algebras, that we call unimodular, and study Toeplitz operators on the Hardy spaces associated to representing measures on these algebras.We show that our class of function algebras is very extensive and that a number of important results for Toeplitz operators and their associated C*-algebras extend to the very general setting we consider. Submitted: July 1. 2001.     

Characterizations of Centralizable Mappings on Algebras of Locally Measurable Operators

A linear mapping φ from an algebra A into its bimodule M is called a centralizable mapping at G ∈ A if φ(AB)=φ(A)B=Aφ(B) for each A and B in A with AB=G. In this paper, we prove that if M is a von Neumann algebra without direct summands of type I₁ and type II, A is a *-subalgebra with M ⊆ A ⊆ LS(M) and G is a fixed element in A, then every continuous (with respect to the local measure topology t(M)) centralizable mapping at G from A into M is a centralizer.