关于Lax-Milgram定理和Céa定理的一个注记

本文研究抽象变分问题(不必要求具有强制性)的Galerhin方法,利用泛函分析理论证明了:若变分问题的Galerkin逼近问题存在唯一解,那么它本身的解存在唯一且可由Galerhin逼近解无限逼近的充要条件是其Galerkin逼近格式具有某种稳定性.此结果是对Lax-Milgram定理和C啨a定理的补充,可以应用于不必具有强制性的变分问题.     

具C^∞系数的非主型方程的Goursat问题

本文以逼近和正则化方法，对一类具Ｃ＾∞系数和数据的非主型方程的Ｇｏｕｒｓａｔ问题证明了Ｃ＾∞解的存在唯一性。     

An inverse eigenvalue problem and an associated approximation problem for generalized K-centrohermitian matrices

A partially described inverse eigenvalue problem and an associated optimal approximation problem for generalized K-centrohermitian matrices are considered. It is shown under which conditions the inverse eigenproblem has a solution. An expression of its general solution is given. In case a solution of the inverse eigenproblem exists, the optimal approximation problem can be solved. The formula of its unique solution is given.     

Problemi gerarchici di punti di Nash: Esistenza e approssimazione nel caso di unicita al livello inferiore

In this paper a two level optimization problem, in which the problem of inferior level is a Nash-problem with general constraints (rappresented by multifunctions) and with a unique solution, is considered. On the problem of inferior level approximation results of the solution are proved, on the problem of superior level existence and approximation results of the solutions are proved.      

Error bounds for euler approximation of a state and control constrained optimal control problem 1

We examine convergence of the Euler approximation to a nonlinear optimal control problem subject to mixed state-control and pure state constraints. We prove that under smoothness, independence, controllability and coercivity conditions at a reference solution of the continuous problem, there exists a locally unique solution to the Euler approximation, for sufficiently fine discretization, which converges to the reference solution with rate proportional to the mesh size.     

Hermitian自反矩阵反问题的最小二乘解

本文研究了Hermitian自反矩阵反问题的最小二乘解及其最佳逼近.利用矩阵的奇异值分解理论,获得了最小二乘解的表达式.同时对于最小二乘解的解集合,得到了最佳逼近解.     

反对称正交对称矩阵反问题

本文讨论一类反对称正交对称矩阵反问题及其最佳逼近．研究了这类矩阵的一些性质，利用这些性质给出了反问题解存在的一些条件和解的一般表达式，不仅证明了最佳逼近解的存在唯一性，而且给出了此解的具体表达式．     

A unique solution of initial value problems for first order impulsive integro-differential equations of mixed type in Banach spaces

In this paper, we investigate initial value problem for first order impulsive integro-differential equation of mixed type in a Banach space. Without any compactness-type assumption, we obtain a unique solution of the equation, an explicit iterative approximation of the solution and an error estimate of the approximation sequence. Our result improves and extends many recent results.     

Banach空间Volterra型二阶微分积分方程两点边值问题的唯一解

在一般序Banach空间中研究了不连续的二阶微分方程两点边值问题解的存在唯一性,给出了解的显式迭代列和误差估计式.     

Existence and approximation of solutions for nonlinear second-order four-point boundary value problems

Applying the method of upper and lower solutions, Leray–Schauder degree theory and one-sided Nagumo condition, we obtain the existence and uniqueness results for a class of nonlinear second-order four-point boundary value problems. By the generalized approximation method, a monotone iteration sequence which converges uniformly to the unique solution of the nonlinear problem and converges quadratically to the unique solution of the linear problem is also obtained.     

Integral boundary value problem for impulsive integro-differential equations in Banach spaces

In this paper, by using the cone theory and monotone iterative technique, we investigate the existence of extremal solutions and unique solution of the integral boundary value problem for a class of first-order impulsive integro-differential equations in a real Banach space. An explicit iterative scheme for the unique solution and an error estimate of the approximation sequence are also derived.     

Banach空间混合型一阶脉冲积分-微分方程初值问题的唯一解

本文在一般的序Banach空间中研究了一阶脉冲混合型积分-微分方程初值问题的唯一解。在比较广泛的上控制条件并且假定所考虑初值问题只有一个上解或下解的假设之下,我们证明了所考虑初值问题的唯一解可以由显形式表达的迭代序列的一致极限得到,并给出了逼近解的迭代序列的误差估计,本文没有使用任何紧型条件。我们的结果是最近一些结果的改进和推广。     

Banach空间积-微分方程两点边值问题

本文利用一些新的微分和积分不等式研究了Ｂａｎａｃｈ空间中积－微分方程的 两点边值问题解的存在唯一性,给出了解的隐式迭代序列和误差估计式．     

Banach空间积-微分方程两点边值问题

本文利用一些新的微分和积分不等式研究了Ｂａｎａｃｈ空间中积－微分方程的 两点边值问题解的存在唯一性,给出了解的隐式迭代序列和误差估计式．     

Banach空间二阶常微分方程两点边值问题迭代求解

本文利用一些新的微分和积分不等式研究Ｂａｎａｃｈ究竟中二阶常微分方程两点边值问题解的存在唯一性,给出了解的迭代序列和误差估计式。     

Stability of best approximation of a convex body by a ball of fixed radius

The finite-dimensional problem of the best approximation (in the Hausdorff metric) of a convex body by a ball of arbitrary norm with a fixed radius is considered. The stability and sensitivity of the solution to errors in specifying the convex body to be approximated and the unit ball of the used norm are analyzed. It is shown that the solution of the problem is stable with respect to the functional and, if the solution is unique, the center of the best approximation ball is stable as well. The sensitivity of the solution to the error with respect to the functional is estimated (regardless of the radius of the ball). A sensitivity estimate for the center of the best approximation ball is obtained under the additional assumption that the estimated body and the ball of the used norm are strongly convex. This estimate is related to the range of radii of the approximating ball.     

Scalar conservation laws with stochastic forcing

We show that the Cauchy Problem for a randomly forced, periodic multi-dimensional scalar first-order conservation law with additive or multiplicative noise is well posed: it admits a unique solution, characterized by a kinetic formulation of the problem, which is the limit of the solution of the stochastic parabolic approximation.     

Explicit iteration and unbounded solutions for fractional integral boundary value problem on an infinite interval

By employing the monotone iterative technique, we not only establish the existence of the unique solution for a fractional integral boundary value problem on semi-infinite intervals, but also develop an explicit iterative sequence for approximating the solution and give an error estimate for the approximation, which is an important improvement of existing results.     

An implicit finite difference scheme for the nonlinear size-structured population model

In this paper we consider the "fully nonlinear" size structured population model. We develop an implicit finite difference scheme to approximate the solution of this nonlinear partial differential equation. The convergence of this approximation to a unique bounded variation solution of this model is obtained. Numerical results to an example problem are presented.     

增生算子方程的具误差的Ishikawa迭代序列的强收敛定理

本文研究了Banach空间中Lipschitz的增生算子T的方程的解的迭代逼近问题.利用Ishikawa迭代法,证明了具误差的Ishikawa迭代序列强收敛到方程的唯一解,得到了一般的收敛率估计式.