共查询到20条相似文献,搜索用时 93 毫秒
1.
《数学物理学报(A辑)》2018,(5)
设A是不含交换中心投影的von Neumann代数,投影P∈A使得P=0, P=I.称可加映射δ:A→A在Ω∈A Lie可导,若δ([A,B])=[δ(A,δ(B)],■A,B∈A,AB=Ω.该文证明,若Ω∈A满足PΩ=Ω,则δ在ΩLie可导当且仅当存在导子τ:A→A和可加映射f:A→Z(A)使得δ(A)=τ(A)+f(A),■A∈A其中f([A,B)=0,■A,B∈A,AB=Ω.特别地,若A是因子von Neumann代数,Ω∈A满足ker(Ω)≠0或ran(Ω)≠H,则可加映射δ:A→A在ΩLie可导当且仅当δ有上述形式. 相似文献
2.
设f(P)是对称区域Ω上的连续函数,其中P∈Ω.若f(P)在Ω中各对称点处函数值的绝对值相等且符号相反时,∫Ωf(P)dΩ=0;当f(P)在Ω中各对称点处的函数值相等时,Ω∫f(P)dΩ=2Ω∫1f(P)dΩ,其中Ω1为Ω"对称的一半".此结论称为积分的广义对称性.通过实例说明了利用此结论可以简化很多积分的计算. 相似文献
3.
给定一个集合Ω,在BCI代数中引入Ω-犹豫模糊P理想的概念,讨论它的一些性质,研究了Ω-犹豫模糊P理想的同态像与同态原像的性质;研究了BCI代数中的Ω-犹豫模糊P理想与犹豫模糊P理想的相互构造,通过Ω-犹豫模糊P理想的水平P理想,讨论了BCI代数中Ω-犹豫模糊P理想的刻画;研究了Ω-犹豫模糊P理想与乘积型BCI代数的Ω-犹豫模糊P理想的关系. 相似文献
4.
设GC_((n))(Ω)为有界开集,f∈L(C_((n))(Ω)),PIΩf(P)=∫s_(((n)(Ω)))(P,Q)f(Q)dσQ,其中PI_((Ω))(P,Q)是锥C_((n))(Ω)内的Poisson核.本文将给出正规化算子(PIΩf(P))/(PIΩXG(P))在锥中的边界极限,所得结果推广了潘国双在半空间中的相关结论. 相似文献
5.
关于特征值问题有限元近似解的最大模估计及其校正加速估计 总被引:1,自引:0,他引:1
本文记通常CooeB空间W_p~m(Ω)(P=2时记为H~m(Ω))的模为||·||_(m,p),m=0,即空间L_p(Ω)的模简记为||·||_p。 设Ω为平面有界区域,边界?Ω分段光滑,则(1)的解存在,且特征值可列: 相似文献
6.
李立康 《应用数学与计算数学学报》1988,(1)
§1.引言设Ω是R~3中的有界区域,且属于C~2.v是正常数.已知:当f∈(L~2(Ω))~3.且||f||0充分小时,Navier—Stokes方程的解存在且唯一.另外,u∈(H~2(Ω)∩H_1~0(Ω))~3,P∈H~1(Ω)\R. 最近,Bernardi讨论三维多面体区域Ω上Stokes方程的有限元解法.有限元空间由分片多项式(关于u为分片特殊三次多项式,关于p为分片常数)构成,进行误差估计时.要求u∈(H~2(Ω)∩H_0~1(Ω))~3,P∈H~1(Ω)\R.当Ω为二维区域上的凸多角形时,Stokes 相似文献
7.
设(Ω,(?),P)为一概率空间,{A_n}n≥1 是(?)中的一串元素,Borel-Cantelli 引理表明:sum from n=1 to ∞ P(A_n)<∞(?)P(A_n i.o.)=0,其中(A_n.i.o.)=(?)A_n.特别地,当{A_n}n≥1为相互独立时,还有:sum from n=1 to ∞ P(A_n)=∞(?)P(A_n i.o.)=1.在本文中,我们先给出 Borel-Cantlli 引理之逆成立的另一个条件,然后利用这一结果来证明(严)平稳过程的一个0-1律。设 T:Ω→Ω是概率空间(Ω,(?),P)上到其自身的一个保测变换,称 T 为遍历的,若对任一B(?),T~(-1)B=B(?)P(B)=0或 P(B)=1.关于遍历变换,我们有: 相似文献
8.
求解Lipschitz型规划全局极小点的改进的填充函数法 总被引:4,自引:0,他引:4
1 引言 考虑问题 (P)min(x), x∈Ω其中F:ΩR~n→R是局部Lipschitz函数,Ω为紧集,且F(x)在Ω内有极小点。文[1,2,3]在一定条件下给出了求解一般非光滑规划全局极小点的填充函数法,并给出了求解的全过程。本文根据文[1,2,3]的思想,为求解(P),结合函数的特点,给出了一种改进 相似文献
9.
考虑不依赖时间的粒子输运问题.不失一般性,还限定问题与能量无关.令P=(r,Ω),其中r和Ω分别表示粒子的位置和运动方向单位矢量.用S(P)表示粒子源;φ(P)表示粒子通量;D(P)表示探测器对粒子通量的响应函数.要计算的是如下积分效应: 相似文献
10.
Let(Ω,,P)be a non-atomic probability space and letT:Ω→Ω be an ergodic measure preserving transformation.For each pair of nonnegative integers n,m we define theoperator T_(n,m),acting on measurable functions as 相似文献
11.
This paper is concerned with the existence, uniqueness and asymptotic behavior of traveling wave fronts for a vector disease model. We first establish the existence of traveling wave fronts by using geometric singular perturbation theory. Then the asymptotic behavior and uniqueness of traveling wave fronts are obtained by using the standard asymptotic theory and sliding method. In addition, our method is also suitable to establish the uniqueness and asymptotic behavior of traveling wave fronts for a cooperative system. 相似文献
12.
N. T. Levashova N. N. Nefedov A. V. Yagremtsev 《Computational Mathematics and Mathematical Physics》2013,53(3):273-283
For a singularly perturbed parabolic equation termed in applications as the reaction-diffusion-advection equation, stationary solutions with internal transition layers (contrast structures) are studied. An arbitrary-order asymptotic approximation of such solutions is constructed, and an existence theorem is proved. An efficient algorithm for constructing an asymptotic approximation of the transition point is proposed. The constructed asymptotic approximation is justified by applying the asymptotic method of differential inequalities, which is extended to the class of problems under study. This method is also used to establish the Lyapunov stability of such stationary solutions. 相似文献
13.
14.
S. M. Roberts 《Journal of Optimization Theory and Applications》1986,48(2):325-339
Singular perturbation problems not amenable to solution by asymptotic methods require special treatment, such as the method of Carrier and Pearson. Rather than devising special methods for these problems, this paper suggests that there may be a uniform way to solve singular perturbation problems, which may or may not succumb to asymptotic methods. A potential mechanism for doing this is the author's boundary-value technique, a nonasymptotic method, which previously has only been applied to singular perturbation problems that lend themselves to asymptotic techniques. Two problems, claimed by Carrier and Pearson to be insoluble by asymptotic methods, are solved by the boundary-value method. 相似文献
15.
S. C. Malaviya 《Proceedings Mathematical Sciences》1967,65(1):62-72
A method for deriving transitional asymptotic expansions from integral representations is described and applied to Anger function and modified Hankel function. The method consists in deriving asymptotic expansions of the function considered as well as its first derivativeat the transition point using conventional methods such as Laplace’s method or the method of steepest descents. Since both the functions considered satisfy a second order linear differential equation, it is possible to obtain asymptotic expansions of higher order derivatives of the functions from the first two expansions. Thus asymptotic expressions for all the derivatives at the transition point are known and a Taylor expansion of the function in the neighbourhood of the transition point can be written. The method is also applicable to the generalized exponential integral, Weber’s parabolic cylinder function and Poiseuille function. 相似文献
16.
《Mathematical Methods in the Applied Sciences》2018,41(2):495-503
A brief review of asymptotic methods to deal with frictionless unilateral contact problems for an elastic layer of finite thickness is presented. Under the assumption that the contact radius is small with respect to the layer thickness, an effective asymptotic method is suggested for solving the unilateral contact problem with a priori unknown contact radius. A specific feature of the method is that the construction of an asymptotic approximation is reduced to a linear algebraic system with respect to integral characteristics (polymoments) of the contact pressure. As an example, the sixth‐order asymptotic model has been written out. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
17.
This paper considers a homotopy perturbation method for approximating multivariate vector-value highly oscillatory integrals. The asymptotic formulae of the integrals and the asymptotic order of the asymptotic method are presented. Numerical examples show the efficiency of the approximation method. 相似文献
18.
Yu. V. Bozhevol’nov N. N. Nefedov 《Computational Mathematics and Mathematical Physics》2010,50(2):264-273
A singularly perturbed initial-boundary value problem is considered for a parabolic equation known in applications as the
reaction-diffusion equation. An asymptotic expansion of solutions with a moving front is constructed, and an existence theorem
for such solutions is proved. The asymptotic expansion is substantiated using the asymptotic method of differential inequalities,
which is extended to the class of problems under study. The method is based on well-known comparison theorems and is a development
of the idea of using formal asymptotics for the construction of upper and lower solutions in singularly perturbed problems
with internal and boundary layers. 相似文献
19.
本文利用两变量展开直接构造边界层项的方法,讨论了一类二阶微分差分方程边值问题的奇摄动解,构造了形式渐近解,作出了余项估计,从而证明了解的存在性. 相似文献
20.
Ryôhei Kakizawa 《Journal of Mathematical Analysis and Applications》2011,378(2):375-386
We are concerned with the determination of the asymptotic behavior of strong solutions to the initial-boundary value problem for general semilinear parabolic equations by the asymptotic behavior of these strong solutions on a finite set. More precisely, if the asymptotic behavior of the strong solution is known on a suitable finite set which is called determining nodes, then the asymptotic behavior of the strong solution itself is entirely determined. We prove the above property by the energy method. 相似文献