半正定复方阵

综述了有关半正定复方阵的主要研究成果，其中包含半正定复方阵在合同下的标准形、半正定复方阵在合同下的全系不变量、半正定复方阵在其Hermite部分及斜Hermite部分之间的Mindowski型行列式不等式以及两个半正定复方阵的，Kronecker乘积仍为半正定的必要且充分条件．     

关于两个Hermite矩阵乘积特征值的一个问题

本文把两个半正定矩阵乘积的特征值的一组不等式，推广到一般Ｈｅｒｍｉｔｅ方阵上去并得到一个相似的结果。     

实方阵的正定性

<正> 众所周知,对于实对称方阵和 Hermite 方阵,都讨论它们的正定性.对于一般的复方阵,K.Hoffman 和 R.Kunze 在他们的著作 《Linear Algebra》的第329页上定义了正定复方阵,并指出,任意一个复方阵 A 正定的必要而充分条件是,A 是正定 Hermite 方阵.但对一般的实方阵没有深入讨论.本文给出正定实方阵(不一定对称)的定义,讨论正定实方阵的特征根性质,并给出正定实方阵在合同下的标准形,以及一个实方阵正定的必要而充分条件.在以下讨论中提到的方阵都指实方阵.     

复正定矩阵的Minkowski不等式

建立了复正定矩阵的几个行列式不等式,将正定Ｈｅｒｍｉｔｅ阵的Ｍｉｎｋｏｗｓｋｉ不等式、 Ｏｓｔｒｏｗｓｋｉ－Ｔａｕｓｓｋｙ不等式推广到了复正定矩阵上,推广改进了一些文献的结果．     

复亚正定矩阵的一些性质

复亚正定矩阵是正定Ｈｅｒｍｉｔｅ矩阵的推广,本文讨论了这一类矩阵张量积的性质,并将实对称矩阵的Ｓｃｈｕｒ定理、华罗庚定理和Ｍｉｎｋｏｗｓｋｉ不等式推广到较为广泛的复矩阵类．     

复正定矩阵的充要条件

本文研究Hermite正定矩阵、实正定矩阵的推广概念复正定矩阵,给出了复方阵复正定性的一些充分必要条件。     

从矩阵迹关系过渡到算子迹关系的一个通用方法(Ⅱ)

周其生等人（１９９７年）给出了一个把半正定Ｈｅｒｍｉｔｅ阵的迹关系推广到正迹类算子的相应关系的通用方法。本文把上述通用方法推广到Ｓｃｈａｔｔｅｎ类算子,并用它得到一些重要的算子迹不等式。     

关于复矩阵乘积的正定性

两复正定矩阵之和必是复正定矩阵,但其积未必是复正定矩阵.研究了复矩阵之积的正定性,给出了复矩阵之积为复正定矩阵的一系列判定条件,获得了一些新的结果,改进并推广了K y Fan T aussky定理及Fe jer定理.     

关于Hermite矩阵乘积的迹的一个不等式

关于Ｈｅｒｍｉｔｅ矩阵乘积的迹的一个不等式陶跃钢（湖北教育学院４３００６０）定理设Ａ，Ｂ均为ｎ阶Ｈｅｒｍｉｔｅ矩阵，其特征值分别为则。ｒ（Ａ）三Ｚ。ｌ。。·ｌ＝１文山在Ａ正定的条件下证得上述定理，并由此给出了Ｈｏｆｆｍａｎ——Ｗｉｅｌａｎｄｔ定理的一...     

关于矩阵迹的平均不等式

关于矩阵迹的平均不等式黄礼平（湘潭矿业学院基础课部４１１２０１）近年来，对矩阵迹的不等式研究活跃，本文给出两个矩阵迹的平均不等式．定理１设Ａ，Ｂ，Ｃ均为ｎ阶半正定Ｈｅｒｍｉｔｅ矩阵，则特别，我们有推论１设Ａ，Ｂ，Ｃ均为ｎ阶正定实对称矩阵，则诸等号当且...     

RECENT PROGRESS ON SPHERICAL HARMONIC APPROXIMATION MADE BY BNU RESEARCH GROUP ——In memory of Professor Sun Yongsheng

As early as in 1990, Professor Sun Yongsheng, suggested his students at Beijing Normal University to consider research problems on the unit sphere. Under his guidance and encouragement his students started the research on spherical harmonic analysis and approximation. In this paper, we incompletely introduce the main achievements in this area obtained by our group and relative researchers during recent 5 years （2001-2005）. The main topics are： convergence of Cesaro summability, a.e. and strong summability of Fourier-Laplace series; smoothness and K-functionals; Kolmogorov and linear widths.     

A unified approach to certain problems of best local approximation

In this paper we study best local quasi-rational approximation and best local approximation from finite dimensional subspaces of vectorial functions of several variables. Our approach extends and unifies several problems concerning best local multi-point approximation in different norms.     

Boundedness for commutators of multipliers on Hardy type spaces

In this paper, we study the commutators generalized by multipliers and a BMO function. Under some assumptions, we establish its boundedness properties from certain atomic Hardy space Hb^p（R^n） into the Lebesgue space L^p with p 〈 1.     

THE 8~(th) INTERNATIONAL CONGRESS ON INDUSTRIAL AND APPLIED MATHEMATICS

<正>August 10-14,2015Beijing,ChinaThe International Congress on Industrial and Applied Mathematics(ICIAM)is the premier international congress in the field of applied mathematics held every four years under the auspices of the International Council for Industrial and Applied Mathematics.From August 10 to 14,2015,mathematicians,scientists     

Towards Excellence in Science Chinese Academy of Sciences

<正>May 26,2014,Beijing Science is a human enterprise in the pursuit of knowledge.The scientific revolution that occurred in the 17th Century initiated the advances of modern science.The scientific knowledge system created by     

Bounds for the zeros of polynomials

Let P(z)=∑↓j=0↑n ajx^j be a polynomial of degree n. In this paper we prove a more general result which interalia improves upon the bounds of a class of polynomials. We also prove a result which includes some extensions and generalizations of Enestrǒm-Kakeya theorem.     

Boundedness of commutators related to Marcinkiewicz integrals on hardy type spaces

In this paper, the authors study the boundedness of the operator [μΩ, b], the commutator generated by a function b ∈ Lipβ(Rn)(0 ＜β≤ 1) and the Marcinkiewicz integrals μΩ, on the classical Hardy spaces and the Herz-type Hardy spaces in the case Ω∈ Lipα(Sn-1)(0 ＜α≤ 1).     

Jacobi polynomials used to invert the laplace transform

Given the Laplace transform F(s) of a function f(t), we develop a new algorithm to find an approximation to f(t) by the use of the classical Jacobi polynomials. The main contribution of our work is the development of a new and very effective method to determine the coefficients in the finite series expansion that approximation f(t) in terms of Jacobi polynomials. Some numerical examples are illustrated.     

Generalization of the interaction between Haar approximation and polynomial operators to higher order methods

In applications it is useful to compute the local average empirical statistics on u. A very simple relation exists when of a function f（u） of an input u from the local averages are given by a Haar approximation. The question is to know if it holds for higher order approximation methods. To do so, it is necessary to use approximate product operators defined over linear approximation spaces. These products are characterized by a Strang and Fix like condition. An explicit construction of these product operators is exhibited for piecewise polynomial functions, using Hermite interpolation. The averaging relation which holds for the Haar approximation is then recovered when the product is defined by a two point Hermite interpolation.