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1.
奇异半线性发展方程的局部Cauchy问题 总被引:9,自引:1,他引:8
本文在Banach空间E中讨论如下问题dudt+1tσAu=J(u),0<tT,limt→0+u(t)=0,其中u:(0,T]E,A是与t无关的线性算子.(-A)是E上C0半群{T(t)}t0的无穷小生成元,常数σ1,J是一个非线性映射EJ→E.它满足局部Lipschitz条件.我们证明了当其Lipschitz常数l(r)满足一定条件时.问题(S)有局部解,且在某函类中解唯一.设J(u)=|u|γ-1u+f(x)(γ>1),E=Lp,EJ=Lpγ时得到了与Weisler[2]在非奇异情形类似的结果. 相似文献
2.
Lipschitz常数缩减的散乱数据插值 总被引:2,自引:0,他引:2
在计算机辅助设计几何中,变差缩减是一个非常重要的概念,本文分析了函数的变差和Lipschitz常数的关系,指出可以用Lipschitz常数来控制变差,由于变差的概念只限于一维的情形,而Lipschitz常数适用于任意维,这样在高维时就可用Lipschitz常数缩减的概念来代替变差缩减的概念,文中构造性地证明了Lipschitz常数缩减的散乱数据插值函数的存在性,并且对这类函数的性质及光滑性条件进行了讨论. 相似文献
3.
三阶非线性常微分方程非线性两点边值问题解的存在性与唯一性 总被引:2,自引:0,他引:2
本文得用Bolzano定理,给出了三阶非线性常微分方程具非线性两点边界条件的边值问题(1)(2)存在解与存在唯一解的一般结果,并将所得结果应用于Lipschitz方程,对Lipschitz方程满足(2),(3)的边值问题给出了解存在与存在唯一解的较具体的充分条件。 相似文献
4.
四阶非线性常微分方程非线性两点边值问题解的存在唯一性 总被引:2,自引:0,他引:2
裴明鹤 《高校应用数学学报(A辑)》1995,(3):285-294
本文利用Bolzano定理,给出了四阶非线性常微微分方程具有非线性边界条件的两点边值问题(1)(2)2,(1)(2)3存在解与存在唯一解的一般性结果,并将所得结果应用于Lipschiz方程,对Lipschitz方程满足边界条件(2)2,(2)3的边值问题给出了存在解与存在唯一解的具体的充分条件。 相似文献
5.
非线性Lipschitz算子的Lipschitz对偶算子及其应用 总被引:3,自引:0,他引:3
在文山中我们对非线性Lipschitz算子定义了其Lipschitz对偶算子,并证明了任意非线性Lipschitz算子的Lipschitz对偶算子是一个定义在Lipschitz对偶空间上的有界线性算子.本文还进一步证明:设C为 Banach空间 X的闭子集,C*L为C的 Lipschitz对偶空间,U为 C*L上的有界线性算子,则当且仅当 U为 w*-w*连续的同态变换时,存在Lipschitz连续算子T,使U为T的Lipschitz对偶算子.这一结论的理论意义在于:它表明一个非线性Lipschitz算子的可逆性问题可转化为有界线性算子的可逆性问题.作为应用,通过引入一个新概念──PX-对偶算子,在一般框架下给出了非线性算子半群的生成定理. 相似文献
6.
关于非线性Lipschitz算子的Soderlind猜想 总被引:2,自引:2,他引:0
设f是以L(f)为最小上界Lipschitz常数,以ρ(f)为谱域半径,以γ(f)为Gerschgorim域半径的有限维非线性Lipschitz算子,本文证明了“存在等价范数‖.‖^*使L^*(f)=r^*(f)的Soderlind猜想;给出反例否定了Soderlind的另一猜想:”存在等价范烤‖.‖ε使Lε使Lε(f)≤ρ(f)+δ的猜想。 相似文献
7.
设。本文证明了N(p)(p≥2)是P的可微函数,并且N(p)在区间[1,∞]上满足Lipschitz条件。设是定义在区间[a,b]上的n个线性无关的连续函数,记给定f∈L∞[a,b],令N(p)=我们称vp(1≤P≤∞)是f的最佳Lp逼近。 相似文献
8.
设f是以L(f)为最小上界Lipschitz常数、以ρ(f)为谱域半径、以r(f)为Gerschgorim域半径的有限维非线性Lipschitz算子.本文证明了“存在等价范数‖·‖使L(f)=r(f)”的Sderlind猜想;给出反例否定了Sderlind的另一个猜想:“存在等价范数‖·‖使L(f)r(f)”(注意r(f)与r(f)的区别),同时也否定了“ε>0,存在等价范数‖·‖ε使Lε(f)ρ(f)+ε”的猜想.作为以上所获结论的应用,本文将有关Daugavet方程的相应结果推广到了非线性算子情形. 相似文献
9.
曾韧英 《数学物理学报(A辑)》1999,(Z1)
该文对定义于局部凸线性拓扑空间X上的泛函引入广义方向导数、广义梯度及满足Lips-chitz条件等概念,证明了它们的几个重要性质,并举例说明这里满足Lipschitz条件的概念是Ba-nach空间情形的严格推广.最后,作为上述结论及方法的应用,讨论定义于X的多目标数学规划,得出若干关于弱有效解的最优性条件. 相似文献
10.
1.引言方程是在国内外引起广泛关注的一类重要的非线性发展方程.文[1]在函数f(s)满足局部 Lip-schitz条件及单调性条件(f(s2)-f(s1))(s2-s1)> 0的假设下得到了(1.1)初边值问题整体弱解的存在与唯一性;文[2]用 Galerkin方法,研究了(1.1)的初边值问题,周期边值问题和初值问题,并在函数f’(s)下方有界的假设下得到了整体强解的存在与唯一性. 本文在有限区域 QT=[0,1]×[0,T](T> 0)上讨论方程(1.1)带有初值条件和边值条件(u(x,t)为未知… 相似文献
11.
In this paper we discuss two-stage diagonally implicit stochastic Runge-Kutta methods with strong order 1.0 for strong solutions of Stratonovich stochastic differential equations. Five stochastic Runge-Kutta methods are presented in this paper. They are an explicit method with a large MS-stability region, a semi-implicit method with minimum principal error coefficients, a semi-implicit method with a large MS-stability region, an implicit method with minimum principal error coefficients and another implicit method. We also consider composite stochastic Runge-Kutta methods which are the combination of semi-implicit Runge-Kutta methods and implicit Runge-Kutta methods. Two composite methods are presented in this paper. Numerical results are reported to compare the convergence properties and stability properties of these stochastic Runge-Kutta methods. 相似文献
12.
D. J. L. Chen 《Numerical Algorithms》2014,65(3):533-554
Singly-implicit Runge-Kutta methods are considered to be good candidates for stiff problems because of their good stability and high accuracy. The existing methods, SIRK (Singly-implicit Runge-Kutta), DESI (Diagonally Extendable Singly-implicit Runge-Kutta), ESIRK (Effective order Singly-implicit Rung-Kutta) and DESIRE (Diagonally Extended Singly-implicit Runge-Kutta Effective order) methods have been shown to be efficient for stiff differential equations, especially for high dimensional stiff problems. In this paper, we measure the efficiency for the family of singly-implicit Runge-Kutta methods using the local truncation error produced within one single step and the count of number of operations. Verification of the error and the computational costs for these methods using variable stepsize scheme are presented. We show how the numerical results are effected by the designed factors: additional diagonal-implicit stages and effective order. 相似文献
13.
Cheng-ming Huang 《计算数学(英文版)》2001,(3)
1. IntroductionWhen considering the applicability of numerical methods for the solution of the delay differential equation (DDE) y'(t) = f(t, y(t), y(t - T)), it is necessary to analyze the error behaviourof the methods. In fact, many papers have investigated the local and global error behaviour ofDDE solvers (cL[1,2,14]). These error analyses are based on the assumption that the fUnctionf(t,y,z) satisfies Lipschitz conditions in both the last two variables. They are suitable fornonstiff … 相似文献
14.
G. Y. Kulikov 《Journal of Applied Mathematics and Computing》2000,7(2):289-318
In this paper we develop a new procedure to control stepsize for Runge-Kutta methods applied to both ordinary differential
equations and semi-explicit index 1 differential-algebraic equations. In contrast to the standard approach, the error control
mechanism presented here is based on monitoring and controlling both the local and global errors of Runge-Kutta formulas.
As a result, Runge-Kutta methods with the local-global stepsize control solve differential or differential-algebraic equations
with any prescribed accuracy (up to round-off errors).
For implicit Runge-Kutta formulas we give the sufficient number of both full and modified Newton iterations allowing the iterative
approximations to be correctly used in the procedure of the local-global stepsize control. In addition, we develop a stable
local-global error control mechanism which is applicable for stiff problems. Numerical tests support the theoretical results
of the paper. 相似文献
15.
In this paper, we focus on the error behavior of Runge-Kutta methods for nonlinear neutral Volterra delay-integro-differential
equations (NVDIDEs) with constant delay. The convergence properties of the Runge-Kutta methods with two classes of quadrature
technique, compound quadrature rule and Pouzet type quadrature technique, are investigated.
相似文献
16.
Ch. Lubich 《Numerische Mathematik》1982,40(1):119-135
Summary The present paper develops the theory of general Runge-Kutta methods for Volterra integrodifferential equations. The local order is characterized in terms of the coefficients of the method. We investigate the global convergence of mixed and extended Runge-Kutta methods and give results on asymptotic error expansions. In a further section we construct examples of methods up to order 4. 相似文献
17.
18.
For a class of methods sufficiently general as to include linear multistep and Runge-Kutta methods as special cases, a concept known as algebraic stability is defined. This property is based on a non-linear test problem and extends existing results on Runge-Kutta methods and on linear multistep and one-leg methods. The algebraic stability properties of a number of particular methods in these families are studied and a generalization is made which enables estimates of error growth to be provided for certain classes of methods. 相似文献
19.
D. Van Dyck R. De Ridder J. De Sitter 《Journal of Computational and Applied Mathematics》1980,6(1):83-85
It is shown how the attainable minimum for the memory requirements of Runge-Kutta methods can be realised for methods of the third order. These economisable third order methods belong to a one parameter sub-family from which two particular members with low error bound are selected. 相似文献
20.
A new class of two-step Runge-Kutta methods for the numerical solution of ordinary differential equations is proposed. These methods are obtained using the collocation approach by relaxing some of the collocation conditions to obtain methods with desirable stability properties. Local error estimation for these methods is also discussed. 相似文献