共查询到20条相似文献,搜索用时 109 毫秒
1.
针对难找到破碎群体平衡方程的精确解和解析方法缺乏的问题,研究两类积分-偏微分方程(破碎群体平衡方程)接受的李群、群不变解、约化积分-常微分方程及精确解.首先采用伸缩变换李群分析方法探寻积分-偏微分方程接受的李群.其次将积分-偏微分方程转化为纯偏微分方程,运用经典李群分析方法计算纯偏微分方程接受的李群.然后利用改进了的李群分析方法结合伸缩变换群和经典李群分析方法获得的结果确定积分-偏微分方程接受的李群.最后找到了积分-偏微分方程接受的李群,给出了积分-偏微分方程的约化积分-常微分方程、群不变解及显式精确解,分析了部分解的动力学行为性质及特征. 相似文献
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再生核空间W_2~2[0,∞)中一类积分──微分方程精确解的表示 总被引:4,自引:0,他引:4
本文作者在文[2]中定义一个再生核空间W_2~2][0,∞),在其中讨论了最佳插值问题,在文[3]中又定义了W_2~2][a,b),在其中讨论了最佳Hermite插值问题,而在文同中给出W_2~2][a,b)中的微分方程定解问题的解析解.本文则定义一个再生核空间W_2~2][0,∞),在其中讨论了积分一微分方程解的存在唯一性,给出积分一微分方程一个定解问题的精确解的表达式,并由精确解表达式直接得出近似解,这种近似解有如下特征:1”。。(x)是由节点拉村上的人x;)的植结出的,当节点系极村在外一上趋于稠密时,。。M一致收敛于精确解u仰,并且误差阳门一。血… 相似文献
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Stokes问题Q_2-P_1混合元外推方法 总被引:2,自引:0,他引:2
考虑Stokes问题的有限元解与精确解插值的Q2-P1混合元的渐近误差展开和分裂外推.首先利用积分恒等式技巧确定了微分方程精确解与有限元插值之间积分式的主项,其次再借助插值后处理和分裂外推技术,得到了比通常的误差估计提高两阶的收敛速度. 相似文献
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给出了 Banach空间中一阶线性脉冲积分 -微分方程初值问题解的存在唯一性的一个新证法 ,改进了已有结果 .利用它讨论了一阶非线性脉冲积分 -微分方程初值问题的解 ,所得结果大大推广了已有的相关结果 . 相似文献
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该文基于一个Riccati方程组,提出了一个新的广义投影Ric cati展开法,该方法直接简单并能构造非线性微分方程更多的新的解析解。利用该算法研究了(2+1)维广义浅水波方程,并求得了许多新的精确解,包括类孤子解和周期解。该算法也能应用到其它非线性微分方程中。 相似文献
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Banach空间中N阶脉冲积分-微分方程边值问题的解 总被引:1,自引:0,他引:1
运用Monch不动点定理,获得了Banach空间中一类N阶非线性混合型脉冲积分-微分方程边值问题解的存在性.最后给出一个三阶无穷脉冲积分-微分方程边值问题的例子来说明文中所给的条件是合理的. 相似文献
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《数学的实践与认识》2017,(23)
利用Darbo不动点定理的一般化结果以及一个脉冲积分不等式,研究Banach空间二阶混合型积分-微分方程两点边值问题解的存在性,获得了其解的两个存在性结果.并给出了一个应用例子. 相似文献
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《数学的实践与认识》2020,(13)
为了给物理学中的动力学行为研究提供依据,更好解释一些物理现象.首先使用分数阶复变换将时空-分数阶MKdV-ZK方程转换为非线性常微分方程组,其次使用除法定理寻求常微分方程组的首次积分,最后使用首次积分求解出原方程的许多精确解,得到了时空-分数阶MKdV-ZK方程的新精确解.数值结果表明首次积分法是有效的,该方法具有简单便捷等优点. 相似文献
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Consider the perturbation analysis for positive definite solution of the nonlinear matrix equation $X-\sum_{i=1}^{m}A_{i}^{*}X^{-1}A_{i}=Q$ which arises in an optimal interpolation problem. Two perturbation bounds for the unique positive definite solution are obtained, and an explicit expression of the condition number for the unique positive definite solution is derived. The theoretical results are illustrated by several numerical examples. 相似文献
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矩阵方程aX2+bX+cE=O的正定解和实对称解 总被引:3,自引:1,他引:2
给出了矩阵方程aX2+bX+cE=O,a,b,c∈R,a≠0有正定解,实对称解的充分必要条件及解的一般形式. 相似文献
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Summary. We consider the problem of minimizing
the spectral condition number of a positive definite matrix
by completion:
\noindent where is
an Hermitian positive definite
matrix, a matrix and is
a free Hermitian matrix. We reduce
this problem to an optimization problem for a convex function
in one variable. Using the minimal solution of this problem
we characterize the complete set of matrices that give the minimum
condition number.
Received October 15, 1993 相似文献
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本文讨论如下内容:1.把有关对称正定(半正定)的一些性质推广到广义正定(半正定)。2.给定x∈Rm×m,∧为对角阵,求AX=x∧在对称半正定矩阵类中解存在的充要条件及一般形式,并讨论了对任意给定的对称正定(半正定)矩阵A,在上述解的集合中求得A,使得 相似文献
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再生核空间W22[0,∞)中一类积分-----微分方程精确 总被引:2,自引:0,他引:2
In this paper, we discuss the definite solution problem ofintegro-differetial equation, give the exact solution to the definitesolution problem of integro-differential equation in space W22 [0,∞) of reproducing kernel. 相似文献
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Xiao-xia Guo 《计算数学(英文版)》2005,23(5):513-526
Based on the fixed-point theory, we study the existence and the uniqueness of the maximal Hermitian positive definite solution of the nonlinear matrix equation X+A^*X^-2A=Q, where Q is a square Hermitian positive definite matrix and A* is the conjugate transpose of the matrix A. We also demonstrate some essential properties and analyze the sensitivity of this solution. In addition, we derive computable error bounds about the approximations to the maximal Hermitian positive definite solution of the nonlinear matrix equation X+A^*X^-2A=Q. At last, we further generalize these results to the nonlinear matrix equation X+A^*X^-nA=Q, where n≥2 is a given positive integer. 相似文献
19.
Hua Dai 《计算数学(英文版)》2004,22(5):671-680
Let $P$ be an $n\times n$ symmetric orthogonal matrix. A real $n\times n$ matrix $A$ is called P-symmetric nonnegative definite if $A$ is symmetric nonnegative definite and $(PA)^T=PA$. This paper is concerned with a kind of inverse problem for P-symmetric nonnegative definite matrices: Given a real $n\times n$ matrix $\widetilde{A}$, real $n\times m$ matrices $X$ and $B$, find an $n\times n$ P-symmetric nonnegative definite matrix $A$ minimizing $||A-\widetilde{A}||_F$ subject to $AX =B$. Necessary and sufficient conditions are presented for the solvability of the problem. The expression of the solution to the problem is given. These results are applied to solve an inverse eigenvalue problem for P-symmetric nonnegative definite matrices. 相似文献
20.
This paper deals with maximum entropy completion of partially specified block-circulant matrices. Since positive definite symmetric circulants happen to be covariance matrices of stationary periodic processes, in particular of stationary reciprocal processes, this problem has applications in signal processing, in particular to image modeling. In fact it is strictly related to maximum likelihood estimation of bilateral AR-type representations of acausal signals subject to certain conditional independence constraints. The maximum entropy completion problem for block-circulant matrices has recently been solved by the authors, although leaving open the problem of an efficient computation of the solution. In this paper, we provide an efficient algorithm for computing its solution which compares very favorably with existing algorithms designed for positive definite matrix extension problems. The proposed algorithm benefits from the analysis of the relationship between our problem and the band-extension problem for block-Toeplitz matrices also developed in this paper. 相似文献