关于二次样条的一点注记

<正> 本文使用下述符号: In={1,2,…,n) In\{1}={2,3,…,n},n∈N,N为自然数集合。1、令△:a=x1相似文献   

A NOTE ON n-PERINORMAL OPERATORS

The study of operators satisfying σja(T) = σa(T) is of significant interest. Does σja(T) = σa(T) for n-perinormal operator T ∈ B(H)ff This question was raised by Mecheri and Braha [Oper. Matrices 6(2012), 725–734]. In the note we construct a counterexample to this question and obtain the following result: if T is a n-perinormal operator in B(H), then σja(T)\{0} = σa(T)\{0}. We also consider tensor product of n-perinormal operators.     

关于Netessine和Rudi库存模型中目标函数的一点注记

Netessine and Rudi(2003)consider a consumer-driven substitution problem with an arbitrary number of products under both centralized management and competition.They obtain analytically tractable solutions,establish concavity of the objective function,i.e.,the expected profit function generated by each product and uniqueness of the equilibrium for the decentralize case.For the centralized case,they indicate that the objective function,i.e.,the expected profit function,might not be concave and not even quasiconcave.In this note we show,for the centralize case,that the objective function is submodular,and partially venfy Netessine and Rudi's observation that the objective function be unimodal in each of the decision variables for some case.     

关于β范空间中单位球面间线性等距扩张的一个注记

In this paper, we give four general results on linear extension of isometries between the unit spheres in β-normed spaces. These results improve the corresponding theorems in β-normed spaces.     

关于“块H-矩阵与块矩阵的谱”一文的注记

完善了"块H-矩阵与块矩阵的谱"一文中的主要结论.进一步,给出了分块矩阵特征值的一个新包含域,并用实例说明了新结论的优越性.     

次可加测度压的一个注记

利用非紧集上拓扑压的定义,对任意一个不变测度和一族紧度量空间上的次可加势函数,引进了一个新的次可加测度压的定义.在某些假设下,对任意一个遍历测度,证明了新定义的次可加测度压等于用生成集定义的次可加测度压.进一步得到了一个逆变分原理,即次可加测度压等于在某个非紧集上的拓扑压.     

Schwarz引理的一个注记

本文中,基于幅角原理和同论理论紧密联系的想法,我们对单复变中经典的Sdlwarz引理给出了一个新的证明.同时,运用同样的方法,我们把Schwarz引理推广到亚纯函数和多连通区域的情形.     

关于算子空间逼近性质的一个注记

考虑算子空间和C*-代数的算子空间逼近性质,强箅子空间逼近性质与分片映射性质之间的某些关系.     

A remark on the Cauchy problem of 1D compressible Navier-Stokes equations with density-dependent viscosity coefficients

This paper is concerned with the Cauchy problems of one-dimensional compressible Navier-Stokes equations with density-dependent viscosity coefcients.By assumingρ0∈L1（R）,we will prove the existence of weak solutions to the Cauchy problems forθ〉0.This will improve results in Jiu and Xin’s paper（Kinet.Relat.Models,1（2）：313–330（2008））in whichθ〉12is required.In addition,We will study the large time asymptotic behavior of such weak solutions.     

注记——学好数学的有效途径

随着新课程标准的实施和新教材的试用，我们所使用的新教材样式设计新颖，增设了旧教材不具有的栏目，如：章头图、阅读材料、研究性学习课趣等；特别是新教材中的每一页的一侧都留下一栏空白，这一栏空白处中除了偶尔有：知识补充说明、几个图形和数学家介绍外，其余什么也投写。教材这么做的意图是什么，对我们学生的数学学习有什么启示和作用呢？