正线性方程组的半正解

通过引入正线性方程组Ax=b的可去变量,得到了没有可去变量的正线性方程组有无穷多个半正解情形的充分必要条件以及有惟一半正解情形的充分必要条件.     

非齐次线性方程组的半正解

线性方程组的不带负分量的非零解向量称为半正解本给出非齐次线性方程组Ax=B (B≠0)的半正解结构,进而得到该类线性方程组有半正解的充分条件和必要条件以及唯一半正解的充要条件。     

线性方程组的正解

讨论了线性方程组正解的若干性质,给出了线性方程组有正解的一个充要条件,以及由此得到的求正解的一般方法,还介绍了正解问题的若干应用.     

关于正线性方程组正解的判定定理

给出正线性方程组正解的概念,给出并证明了正线性方程组正解的若干判别方法,对教学有一定的指导意义.     

正线性方程组正解的判别

本文给出了正线性方程组正解的概念，给出了正线性方程组正解的若干判别方法     

带有Neumann边界的方程组多个正解存在性

研究带有Neumann边界条件的拟线性方程组的正解问题.在不同参数条件下,主要利用特征值理论和Nehari流形给出了方程组正解的存在性和多解性.这一结论很好的推广了已有的结果.     

随机系数线性方程组正解的一种数值解法

通过建立摩擦片磨损量的数学模型,引出了随机系数线性方程组的求解问题以及对其解的统计分布上的分析,给出了一个相关定理,阐明了其分布是对称分布,且其正分量出现的概率大于零,从而为讨论此类方程组解的问题提供了统计分析的依据.同时,还利用优化思想对该随机系数线性方程组的正解加以讨论,给出在简约梯度法下正解数值近似解的算例.     

一类捕食——食饵模型正平衡解的整体分歧

讨论了一类改进的Leslie-Gower和Holling-Type Ⅱ型捕食-食饵模型对应的平衡态系统正解的结构.以捕食者的出生率b为分歧参数,利用局部分歧理论和整体分歧理论,得到了此平衡态系统正解的存在性与参数b的关系,即当b适当大时,该平衡态系统具有共存正解.     

基于Nehari等变分法的拟线性方程组多重正解的证明

研究了含有权函数和Hardy-Sobolev临界指标的拟线性方程组,运用Nehari等变分法,证明在一定条件下椭圆方程组正解的存在性以及多重性.     

带有非线性边界条件的拟线性方程组正解的存在性

在这篇文章中,我们讨论了带有非线性边界条件和权函数的的拟线性方程组,主要借助对Nehari流形的分析,在合适的参数条件下得到了方程组至少有两个不同的非平凡正解.     

集中力作用下的半平面边缘裂纹问题

讨论了半平面中的倾斜裂纹问题。集中力作用于裂纹表面上,或作用于开裂半平面的边界上。利用有理保角映像函数方法求解这个问题,同时得到了闭合形式的解。最后,给出了二个数值例子和计算结果。     

矩形片筏基础的挠度分析

工程上对片筏的力学分析，通常采用温克勒地基模型，且假定床基系数是常量。本则认为床基系数是坐标的函数，考虑了具有线性变化床基系数的地基上的片筏，利用伽辽金法求得周边固支片筏在均布荷载作用下的挠度。所得结果颇具一般性且实用价值更高。     

An Exact Solution to Linear Programming Using an Interior Point Method

This paper presents sufficient conditions for optimality of the Linear programming (LP) problem in the neighborhood of an optimal solution, and applies them to an interior point method for solving the LP problem. We show that after a finite number of iterations, an exact solution to the LP problem is obtained by solving a linear system of equations under the assumptions that the primal and dual problems are both nondegenerate, and that the minimum value is bounded. If necessary, the dual solution can also be found.     

Second-order necessary conditions in a domain optimization problem

Second-order necessary conditions of the Kuhn-Tucker type for optimality in a domain optimization problem are studied. The second variation, corresponding to a boundary variation, of the solution to a boundary-value problem is shown to exist and is given as the solution of a boundary-value problem of the same type. The boundary data are shown to be given in terms of the solution and the first variation of the solution. From these results, the second variation of the objective function is calculated to derive second-order necessary conditions of the Kuhn-Tucker type.A part of this work was presented under the title of Second Variation and Its Application in a Domain Optimization Problem at the 4th IFAC Symposium on Control of Distributed-Parameter Systems, Los Angeles, California, 1986 and appeared in the Proceedings of the Symposium, Control of Distributed Parameter Systems, Pergamon Press, 1986. The author wishes to express his thanks to Professor Y. Sakawa of Osaka University for his encouragement. The author thanks the referees for critical reading and helpful comments.     

An extragradient-type algorithm for non-smooth variational inequalities

In this paper we study extragradient-type methods to solve variational inequality problems involving maximal monotone point-to-set operators. We will show, using an example, that, in this case, to achieve convergence to the solution set of sequences generated by extragradient methods it is necessary, in the search of the auxiliary point and its suitable image by the involved operator, to enlarge the set of possible search directions. Such an enlargement, a generalization of the ε-subgradient, is known and we use it to overcome this failure of the extragradient-methods. We propose a new algo-rithm and prove that it generates a sequence convergent to a solution point of the problem also when the operator is point-to-set     

Logistic型方程周期解和概周期解的存在性

In this paper, we study the Logistic type equation x= a（t）x -b（t）x^2＋ e（t）. Under the assumptions that e（t） is small enough and a（t）, b（t） are contained in some positive intervals, we prove that this equation has a positive bounded solution which is stable. Moreover, this solution is a periodic solution if a（t）, b（t） and e（t） are periodic functions, and this solution is an almost periodic solution if a（t）, b（t） and e（t） are almost periodic functions.     

Time-space polynomial martingales cenerated by a discrete-time martingale

We investigate, for a given martingaleM={M _n: n0}, the conditions for the existence of polynomialsP(·,·) of two variables, time and space, and of arbitrary degree in the latter, such that{P(n, M _n)} is a martingale for the natural filtration ofM. Denoting by the vector space of all such polynomials, we ask, in particular, when such a sequence can be chosen so as to span . A complete necessary and sufficient condition is obtained in the case whenM has independent increments. For generalM, we obtain a necessary condition which entails, under mild additional hypotheses, thatM is necessarily Markovian. Considering a slightly more general class of polynomials than we obtain necessary and sufficient conditions in the case of general martingales also. It is moreover observed that in most of the cases, the set determines the law of the martingale in a certain sense.The research of this author was supported by the National Board of Higher Mathematics, Bombay, India.     

关于算子方程AX=XAX与AX=XA=XAX

用A的不变子空间作参数，给出了算子方程AX＝XAX的全部解。当A是单射或稠值域时，或者当A是正规算子时，给出了算子方程AX＝XA＝XAX的全部解。我们还给出正规算子X是算子方程AX＝XZ＝XAX的解的充分必要条件。     

On Chebychev Acceleration Procedures for Alternating Direction Iterative Methods

The solution of large sparse systems of linear equations arising,for example, from the numerical solution of elliptic partialdifferential equations is considered, with reference to theacceleration technique commonly known as Chebychev acceleration.In particular its application to alternating direction iterative(A.D.I.) methods is compared with the more standard techniquessuch as successive overrelaxation. It is conjectured that inmost circumstances a suitable A.D.I. strategy is that of applyingChebychev semiiteration to an A.D.I. process with a single A.D.I.parameter. It is shown that under general conditions this procedure maysometimes produce faster convergence than the usual multiparameterA.D.I. procedure.     

一类非线性双曲型方程Goursat问题的奇摄动

本文研究一类非线性奇摄动问题：在适当的假设下，讨论了相应问题解的存在性和唯一性，构造了其解的形式渐近展开式，并证明了它的一致有效性。