线性矩阵方程的斜Hermit{P,k+1}Hamilton解

给定矩阵P∈C~(n×n)且P~*=-P=P~(k+1).考虑了矩阵方程AX=B存在斜Hermite{P,k+1}(斜)Hamilton解的充要条件,并给出了解的表达式.进一步,对于任意给定的矩阵∈C~(n×n),给出了使得Frobenius范数‖-‖取得最小值的最佳逼近解∈C~(n×n).当矩阵方程AX=B不相容时,给出了斜Hermite{P,k+1}(斜)Hamilton最小二乘解,在此条件下,给出了对于任意给定矩阵的最佳逼近解.最后给出一些数值实例.     

关于距离矩阵的最佳欧氏逼近

Mathar讨论了在范数‖·‖_p~(s)下距离矩阵的最佳欧氏逼近问题。本文把这一结果推广到范数‖·‖_u~(s),这里‖·‖_u是任意正交不变范数,并指明对任意的s,E_n总提供最佳欧氏逼近。控制不等式和对称标尺函数在本文起基本的作用。     

关于矩阵方程AX+YB=C反问题的极小 Frobenius范数对称解

在线性约束下矩阵束最佳逼近问题中,对给定的条件做一改变,解决了一个矩阵束最佳逼近问题.设A、B、C都是m×n阶矩阵,当A和B满足同时奇异值分解(SSVD)时,解决了一个关于X,Y的矩阵方程AX+YB=C的反问题即求X∈SRn×n,Y∈SRm×m,使得满足‖AX+YB-C‖F=min,得到了其Frobenius范数对称解.     

关于抛物型方程Crank—NicholSon格式的敛速估计

[1]中给出了解抛物型方程广义Galerkin方法Crank-Nicholson格式的斂速估计是‖U~(?)-u‖_0=0(h~2+τ~(3/2))。本文指出该格式的斂速估计是‖U~(?)-u(nτ)‖_0=O(h~2+τ~2)并证明了该格式按‖·‖_(0,h)范数关于初值是绝对稳定的。     

求AX=B的最小二乘解的一种迭代法

提出了梯度矩阵(ΔF(x))的概念,构造了一种迭代法求最小二乘问题‖AX-B‖=min。通过这种方法,给定初始矩阵X1,在没有舍入误差的情况下,经过有限步迭代,找到它的一个解。并且,通过选择一种特殊的初始矩阵,得到它的最小范数解X*。另外,给定矩阵X0,通过求最小二乘问题min‖AX-B‖(其中B=B-AX),得到它的最佳逼近解。     

矩阵方程ATXA=D的反对称次对称最小二乘解

该文研究的问题为给定A∈R n×m,D∈Rm×m求X∈ASRn×n,使得‖ATXA-D‖F=min.这里ASRn×n表示全体n×n阶反对称次对称矩阵的集合,‖·‖表示Frobinius范数;利用矩阵对的标准相关分解(CCD),得到了该问题的通解表达式及矩阵方程ATXA=D有反对称次对称解的充分必要条件.     

矩阵方程的三对角中心对称最小二乘解

给出矩阵方程AX=B存在三对角中心对称解的充分必要条件,并且给出AX=B的特殊最小二乘解,即对任意给定A,B∈Rm×n,寻求三对角中心对称矩阵X(X∈Rn×n),使得‖AX-B‖最小.     

最终严格对角占优矩阵逆矩阵无穷范数上界的进一步研究

研究矩阵条件数计算中,最终严格对角占优矩阵A的逆矩阵A~(-1)无穷范数‖A~(-1)‖_∞的上界估计问题,利用Nekrasov矩阵逆矩阵无穷范数已有的带有参数的几个估计式,在矩阵A的定义式的基础上,得到了‖A~(-1)‖_∞的一些新结果.     

空间BMO_ (D)和VMD_ (D)的刻画与zhu Kehe猜想

通过构造反例,指出了:f(Z)∈BMO(?)(D))的充要条件是 H_f,H_(?)有界;厂(Z)∈VMO(?)(D)的充要条件是 H_f,H_(?)是紧的,都是不成立的.同时证明了‖·‖_1是 BMO_(?)(D)上的范数,但不是完备的;‖·‖_i(i=2,3)不是 BMO(?);(D)上的范数,而是 BMO(?)(D)上的完备范数且‖·‖_2和‖·‖_3是等价的.     

自反阵的广义特征值反问题

讨论如下广义特征值反问题:给定矩阵X,对角阵Λ和广义反射阵P,求自反阵A,B使得AX=BXΛ,给出了(A,B)的一般表达式.我们把上述问题解的全体记为SAB.然后,讨论了上述问题的最佳逼近问题:给定任意矩阵A*,B*,求矩阵(A~,B~)∈SAB,使得在F-范数意义下(A~,B~)为(A*,B*)的最佳逼近.证明了此问题有惟一解,并给出解的表达式,算法及数值例子.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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