Identities of representations of nilpotent lie algebras

Lret N be a nilpotent of class 2 Lie algebra with one-dimensional centre C = Kc over an infinite field K and let p : N → End_k:(V) be a representation of N in a vector space V such that p(c) is invertible in End_k(V). We find a basis for the identities of the representation p. As consequences we obtain a basis for all the weak polynomial identities of the pair (M₂:(K), s1₂(K)) over an infinite field K of characteristic 2 and describe the identities of the regular representation of Lie algebras related with the Weyl algebra and its tensor powers.     

On the Moore-Penrose inverse, EP Banach space operators, and EP Banach algebra elements

The main concern of this note is the Moore-Penrose inverse in the context of Banach spaces and algebras. Especially attention will be given to a particular class of elements with the aforementioned inverse, namely EP Banach space operators and Banach algebra elements, which will be studied and characterized extending well-known results obtained in the frame of Hilbert space operators and C^∗-algebra elements.     

一类abundant半群的构造

本文讨论ａｂｕｎｄａｎｔ半群上中间幂等元的性质，研究具有正规中间幂等元的ｑｕａｓｉ－ａｄｅｑｕａｔｅ半群及若干极端情形，并分别给出各类半群的构造．     

A CLASS OF NATURALLY ORDERED ABUNDANT SEMIGROUPS WITH A GREATESTIDEMPOTENT

1PreliminariesInthissectionwepresentsomebasicresultsonPalterlyorderedSendgroups,whichwillbeusedfrequentlyinthisPaperThefollowingresultsarequotedfromBlythandMcFaddenl3],justastheysay)whichisalmostpartofthebaulk-lore"ofthetheoryoforderedsetwouPS.Theorem1.1Let(S,S)beanorderedsendgroupwiththesetEofidempotents.Supposethate,jEEwitheSI.Thenel,fe,jef,efeEE.Moreover,ifSisnaturallyorderedthenefe=e.Corollary1.2IfSisnaturallyorderedandhasagreatestidempotentattheneke=eforanyeeE.Inwhatfollows,Sde…     

方程x＋y=xyz的正整数解及其应用

本文探讨了非线性方程x＋y=xyz的正整数解，月个正整数的最大公因数和最小公倍数的关系。将结果应用在方程gcd（α1，α2，…，αn）＋1cm（α1，α2，…，αn）=α1，α2，…，αn的求解问题上。     

On the Approximation of Denotational Mu-Semantics

A signature gives rise to a language L(Var) by extending with variables x Var and binding constructs x and x, corresponding to least and greatest fixed points respectively. The natural denotational models for such languages are bicomplete dcpos as monotone -algebras. We prove that several approximating denotational semantics have the usual compositional semantics as their limit. These results provide techniques for relating syntactic and semantic concepts such as in full abstraction or completeness proofs. In the presence of an involutive antitone map on a bicomplete dcpo D we may translate the language L(Var) into one with least fixed points only such that meanings are preserved. This allows an approximative semantics where least and greatest fixed points are simultaneously approximated by unwindings in the syntax, provided that the limit semantics is substitutive. We discuss the principal difficulties of simultaneous unwindings in the absence of such semantic negations.     

分区域函数的二重积分法

就绝对值函数、极大极小项函数及取整函数三种典型形式讨论分区域函数二重积分的一般方法,并借助实例给予说明．