von Neumann代数中套子代数上的Lie导子

本文对因子von Neumann代数中套子代数上的线性映射L:alg_Mβ→M满足L(AB—BA)=L(A)B-BL(A)+AL(B)-L(B)A( A,B∈alg_Mβ)进行了刻划,证明了存在线性函数h:alg_Mβ→C;且对任意A,B∈alg_Mβ,有h(AB—BA)=0和算子T∈M,使得对任意X∈alg_Mβ,都有L(X)=XT-TX+h(X)I.     

Von Neumann代数中套子代数上的导子

本文研究因子VonNeumann代数中套子代数上的导子．证明了因子VonNeumann代数中套子代数上的任何导子都是内导子．     

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。     

三角代数上的非线性(m,n)-高阶导子

设m和n是任意固定的非零整数且(m+n)(m-n)≠0,u是一个|mn(m+n)|-无挠的三角代数,D={d_k}_(k∈N)是u上的一个(m,n)-高阶可导映射.本文证明了:三角代数u上的每一个(m,n)-高阶可导映射都是高阶导子.作为结论的应用,得到了套代数或|mn(m+n)|-无挠的上三角分块矩阵代数上的每一个(m,n)-高阶可导映射都是高阶导子.     

导算子范数的一个估计

In this paper, a derivation δ_AB mapping into a ideal I of B(H) is considered, when A,B ∈B(H) and I is a norm ideal. If Ran(δ_AB)?I, let δ_AB:B(H)→I denote the induced operator and let λ be the scalar such that A- λ∈I, B-λ∈I, we estimate the norm of δ_AB as follows‖A-λ‖+‖B-λ‖≥‖δ_AB‖≥‖A- λ‖+‖B-λ‖ when W_N(A-λ)∩W_N(λ - B)≠?, where W_N(A- λ) denotes the normalized maximal numerical range and ‖A-λ‖ denotes the norm of A-λ∈I. In particular when I=C_p(lp, we prove that ‖δ_AB‖_p=‖A-λ‖_p+‖B-λ‖_p if and only if ‖A-λ‖=‖A-λ‖_p and W_N(A-λ)∩W_N(λ-B)≠?. At last, some examples show that the estimate as above is exact.     

关于局部导子的一个注记

本文推广Ｋａｄｉｓｏｎ关于局部导子的一个定理并给出十分简单的证明。     

半素环的(1,σ)导子扩张

本文给出了半素环的自同构和（ １,σ）导子的扩张命题,这推广了［１］中的一些结论,然后借助半素环的广义中心里的幂等元在（１,σ）导子扩张模上建立起拓扑空间,从拓扑学角度给出（１,σ）导子扩张模的结构定理．     

TUHF代数上的Lie导子

证明了TUHF代数丁上的Lie导子L形如D l．其中D是T上的结合导子，l是从T到它的中心Z上的线性映射且零化T中的括积．     

4维幂零李代数的导子与triple导子

利用导子和triple导子的定义,刻画了特征不等于2的代数闭域上4维幂零李代数的导子和triple导子.     

JBW-代数上的局部导子

本文证明了JBW-代数上的局部导子是导子,举反例说明了JBW-代数上的局部内导子未必是内导子,并且给出了JBW-代数的一个充要条件使得它上的局部内导子是内导子,     

Norm Attainability of Elementary Operators and Derivations

ＮｏｒｍＡｔｔａｉｎａｂｉｌｉｔｙｏｆＥｌｅｍｅｎｔａｒｙＯｐｅｒａｔｏｒｓａｎｄＤｅｒｉｖａｔｉｏｎｓＪｉＧｕｏｔｉｎｇ（吉国兴）ａｎｄＤｅｆｆｅｎｇｋｅ（杜鸿科）（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｈｅｍａｔｉｃｓ，ＳｈａａｎｘｉＮｏｒｍａｌＵｎｉｖ...     

Derivations and isomorphisms of certain reflexive operator algebras

In this paper, we will prove that every derivation of completely distributive subspace lattice (CDS) algebras on Banach space is automatically continuous. This is new even in the Hilbert space case. As an application of this result, we obtain that every additive derivation of nest algebras on Banach spaces is inne. We will also prove that every isomorphism between nest algebras on Banach space is automatically continuous, and in addition, is spatial. Research supported by NSF of China and YSF of Shandong     

自反算子代数的导子和同构

本文证明了：Ｂａｎａｃｈ空间上完全分配格代数间的导子都是自动连续的；进而证明了套代数的可加导子是内的，套代数间的代数同构是自动连续的、空间的     

Central Extensions and Derivations of the Lie Algebras of Skew Derivations for the Quantum Torus

ABSTRACT

In this article, we study the central extensions and derivations of the Lie algebra of skew derivations for the quantum torus. The results of the article generalize those obtained in Jiang and Meng (1998a Jiang , C. , Meng , D. ( 1998a ). The derivation algebra of the associative algebra C _q [X, Y, X ^?1, Y ^?1] . Comm. Algebra 26 : 1723 – 1736 . [CSA] [Taylor &; Francis Online], [Web of Science ®] , [Google Scholar] b Jiang , C. , Meng , D. ( 1998b ). The automorphism group of the derivation algebra of the Virasoro-like algebra . Adv. Math. (China) 27 : 175 – 183 . [CSA]  [Google Scholar]) and Kirkman et al. (1994 Kirkman , E. , Procesi , C. , Small , L. ( 1994 ). A q-analog for the Virasoro algebra . Comm. Algebra 22 : 3755 – 3774 . [CSA] [Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]).     

Optimal Maximum Norm Estimates and Superconvergence for GDM on Two point Boundary Value Problems

§１．ＩｎｔｒｏｄｕｃｔｉｏｎＲｅｃｅｎｔｌｙ,Ｌｉａｎｄｏｔｈｅｒａｕｔｈｏｒｓｄｉｄｅｘｔｅｎｓｉｖｅａｎｄｄｅｅｐｒｅｓｅａｒｃｈｏｎｔｈｅｔｈｅｏｒｙａｎｄａｐ－ｐｌｉｃａｔｉｏｎｏｆｇｅｎｅｒａｌｉｚｅｄｄｉｆｅｒｅｎｃｅｍｅｔｈｏｄｓ（ｓ...     

Norm equality for a basic elementary operator

Let be the algebra of bounded linear operators on a Hilbert space H. For , define the elementary operator M_A,B by M_A,B(X)=AXB (). We give necessary and sufficient conditions for any pair of operators A and B to satisfy the equation ‖I+M_A,B‖=1+‖A‖‖B‖, where I is the identity operator on H.     

Norm statistics and the complexity of clustering problems

In this paper we introduce a new class of clustering problems. These are similar to certain classical problems but involve a novel combination of ?_p-statistics and ?_q norms. We discuss a real world application in which the case p=2 and q=1 arises in a natural way. We show that, even for one dimension, such problems are NP-hard, which is surprising because the same 1-dimensional problems for the ‘pure’ ?₂-statistic and ?₂ norm are known to satisfy a ‘string property’ and can be solved in polynomial time. We generalize the string property for the case p=q. The string property need not hold when q≤p−1 and we show that instances may be constructed, for which the best solution satisfying the string property does arbitrarily poorly. We state some open problems and conjectures.