首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 109 毫秒
1.
2.
In this paper, the boundary control problem of a distributed parameter system described by the Schr(o)dinger equation posed on finite interval α≤ x ≤β:{iyt yxx |y|2y = 0,y(α,t) = h1(t),y(β,t) = h2(t) for t > 0 (S)is considered. It is shown that by choosing appropriate control inputs (hj), (j = 1,2) one can always guide the system (S) from a given initial state ψ∈ Hs(α,β),(s ∈ R) to a terminal state ψ∈ Hs(α,β), in the time period [0, T]. The exact boundary controllability is obtained by considering a related initial value control problem of Schr(o)dinger equation posed on the whole line R. The discovered smoothing properties of Schr(o)dinger equation have played important roles in our approach; this may be the first step to prove the results on boundary controllability of (semi-linear) nonlinear Schr(o)dinger equation.  相似文献   

3.
<正>Motivated by an animal territoriality model,we consider a centroidal Voronoi tessellation algorithm from a dynamical systems perspective.In doing so,we discuss the stability of an aligned equilibrium configuration for a rectangular domain that exhibits interesting symmetry properties.We also demonstrate the procedure for performing a center manifold reduction on the system to extract a set of coordinates which capture the long term dynamics when the system is close to a bifurcation.Bifurcations of the system restricted to the center manifold are then classified and compared to numerical results.Although we analyze a specific set-up,these methods can in principle be applied to any bifurcation point of any equilibrium for any domain.  相似文献   

4.
Let M be a compact connected 3-submanifold of the 3-sphere S~3 with one boundary component F such that there exists a collection of n pairwise disjoint connected orientable surfaces S = {S_1, ···, S_n} properly embedded in M, ?S = {?S_1, ···, ?S_n}is a complete curve system on F. We call S a complete surface system for M, and ?S a complete spanning curve system for M. In the present paper, the authors show that the equivalent classes of complete spanning curve systems for M are unique, that is, any complete spanning curve system for M is equivalent to ?S. As an application of the result,it is shown that the image of the natural homomorphism from the mapping class group M(M) to M(F) is a subgroup of the handlebody subgroup Hn.  相似文献   

5.
For a closed orientable surface Sg of genus not smaller than 2,C(Sg) is the curve complex on S g whose vertices consist of the isotopy classes of nontrivial circles on Sg. It has been showed that any two vertices in C(Sg) can be connected by an edge path,and C(Sg) has an infinite diameter. We show that for 0 ≤i≤3g-5,two i-simplices can be connected by an(i +1)-path in C(Sg),and the diameter of C(Sg) under such a distance is infinite.  相似文献   

6.
It is well known that certain isotopy classes of oseudo-Anosov maos on a Riemann surface S of non-excluded type can be defined through Dehn twists tα and tβ along simple closed geodesics α and β on S,respectively. Let G be the corresponding Fuchsian group acting on the hyperbolic plane H so that H/G≌S.For any point α∈S,define S = S/{α}.In this article, the author gives explicit parabolic elements of G from which he constructs pseudo-Anosov classes on S that can be projected to a given pseudo-Anosov class on S obtained from Thurston's construction.  相似文献   

7.
A 2-(v,k, l) design D=(Ω,B) is a system consisting of a finite set Ω of v points and acollection B of k-subsets of Ω, called blocks, such that any 2-subset of Ω is contained in exactlyone bled. We shall always assume that 2 < k < v.Let G S AutD be a group of automorphisms of a 2-(v, k, 1) design D. G is said to be blocktransitive (block primitive) on D if G is transitive (primitive, respectively) on B. G is said tobe point transitive (point primitive) on D if G is transitive (primiti…  相似文献   

8.
This paper investigates a class of nonlinear elliptic equations on a fractal domain. We establish a strong Sobolev-type inequality which leads to the existence of multiple non-trivial solutions of △u+ c(x)u = f(x, u), with zero Dirichlet boundary conditions on the Sierpihski gasket. Our existence results do not require any growth conditions of f(x,t) in t, in contrast to the classical theory of elliptic equations on smooth domains.  相似文献   

9.
On spinors     
For a 2^n-dimensional complex Hermitian vector space S, we prove that any unitary basis of S can be explained as an augmented spinor structure on S. By using this explanation, a SpinC(2n)- action on S is equivalent to an action on a subset of augmented spinor structures. The latter action is a little easy to be understood, and is shown in the last part of this paper. Such kind of understanding could be of use to the discussions of Hermitian manifolds and spin manifolds, especially could help to find connections and elliptical operators.  相似文献   

10.
The existence of a pathwise unique strong solution for the stochastic differentialequation(S.D.E.)with Poisson jumps in n-dimensional space without continuityassumption on drift coefficient,which even can be greater than linear growth,andwithout Lipschitz condition on diffusion coefficients is obtained.Then the existence of apathwise stochastic optimal Bang-Bang control for a very much non-linear systemwithPoisson jumps in n-dimensional space is derived.The result is also applied to obtain amaximum likelihood estimate(MLE) of parameter for some continuous,S.D.E.withnon-Lipschitz oeffieients in n-dimensional space.  相似文献   

11.
令S(P)为P-反演半群,本文借助于P-核正规系来刻画S(P)上的强P-同余,证明了S(P)上的任一正则P-同余可以决定S(P)的一个P-核正规系;反之,S(P)的任一P-核正规系可以决定S(P)上的一个正则P-同余.  相似文献   

12.
范兴奎  陈倩华 《数学杂志》2004,24(6):655-660
令S(P)为E-反演P-半群.本文用核与迹研究了S(P)上的强P-同余.证明了S(P)的任一强P-同余对,可以决定S(P)上的一个强P-同余;反之,S(P)上的任一强P-同余,可以决定S(P)的一个强P-同余对。  相似文献   

13.
P-反演半群上的强P-同余   总被引:9,自引:0,他引:9  
范兴奎  陈倩华 《数学进展》2004,33(4):434-440
本文介绍了P-反演半群S(P)的概念,借助于核与迹刻画了P-反演半群上的强P-同余,并且证明了S(P)上的任一强P-同余可以决定S(P)的一个强P-同余对,反之S(P)的任一强P-同余对,可以决定S(P)上的一个强P-同余.  相似文献   

14.
In this paper,we first give the concept of weakly P-inversive semigroup S(P).Then we describe the strong P-congruences on S(P)in terms of their P-kernel normal systems.It is proved that there is a bijection between the strong P-congruences and the P-kernel normal systems.Finally,it is also prove that the lattice of strong P-congruences and the lattice of P-kernel normal systems on S(P)are isomorphic.  相似文献   

15.
本文利用核-迹方法,研究了弱P-反演半群上的强P-同余.给出了强P-同余对和强P-同余关系之间的结构定理.  相似文献   

16.
In this paper, we describe strong P-congruences and sublattice-structure of the strong P-congruence lattice CP(S) of a P-inversive semigroup S(P). It is proved that the set of all strong P-congruences CP(S) on S(P) is a complete lattice. A close link is discovered between the class of P-inversive semigroups and the well-known class of regular ⋆-semigroups. Further, we introduce concepts of strong normal partition/equivalence, C-trace/kernel and discuss some sublattices of CP(S). It is proved that the set of strong P-congruences, which have C-traces (C-kernels) equal to a given strong normal equivalence of P (C-kernel), is a complete sublattice of CP(S). It is also proved that the sublattices determined by C-trace-equaling relation θ and C-kernel-equaling relation κ, respectively, are complete sublattices of CP(S) and the greatest elements of these sublattices are given.  相似文献   

17.
把Reilly对逆半群的幂等元集合的正规划分的概念推广到纯正半群,用它从另一角度刻画。了纯正半群上强同余的结构.并刻画了具有T关系的两个强同余的联和交的正则核正规系,又讨论了纯正半群上的Clifford同余,给出了最小Clifford同余的刻画.  相似文献   

18.
缪惠芳  郭晓峰 《数学研究》2005,38(4):339-345
对强连通有向图D的一个非空顶点子集S,D中包含S的具有最少弧数的强连通有向子图称为S的Steiner子图,S的强Steiner距离d(S)等于S的Steiner子图的弧数. 如果|S|=k, 那么d(S)称为S的k-强距离. 对整数k≥2和强有向图D的顶点v,v的k-强离心率sek(v)为D中所有包含v的k个顶点的子集的k-强距离的最大值. D中顶点的最小k-强离心率称为D的k-强半径,记为sradk(D),最大k-强离心率称为D的k-强直径,记为sdiamk(D). 本文证明了,对于满足k+1≤r,d≤n的任意整数r,d,存在顶点数为n的强竞赛图T′和T″,使得sradk(T′)=r和sdiamk(T″)=d;进而给出了强定向图的k-强直径的一个上界.  相似文献   

19.
关于Poisson群胚的结构   总被引:3,自引:0,他引:3  
贺龙光 《数学学报》1999,42(5):803-808
令(ΓP,α,β)是Poisson群胚.如果它的每个α-纤维与β-纤维至多交于一点,则Γ在任一点x的特征分布有直和分解△(x)=△α(x)+△β(x),其中△α(x)Txα-1(u),△β(x)Txβ-1(u)且它们都是△(x)的辛子空间.由此得到辛叶Sx的辛子流形S和S,使在映射α之下,S辛微分同胚于P中辛叶Su,在映射β之下,S反辛微分同胚于P中辛叶Sv(定理4和5).对于一般的Poisson群胚,也可得到类似的S和S,它们差一局部辛微分同胚是唯一确定的(定理6).把以上结果用于辛群胚,还可得到一些更具体的性质(定理7及其推论).  相似文献   

20.
One of the main tools for including decision maker (DM) preferences in the multiobjective optimization (MO) literature is the use of reference points and achievement scalarizing functions [A.P. Wierzbicki, The use of reference objectives in multiobjective optimization, in: G. Fandel, T. Gal (Eds.), Multiple-Criteria Decision Making Theory and Application, Springer-Verlag, New York, 1980, pp. 469–486.]. The core idea in these approaches is converting the original MO problem into a single-objective optimization problem through the use of a scalarizing function based on a reference point. As a result, a single efficient point adapted to the DM’s preferences is obtained. However, a single solution can be less interesting than an approximation of the efficient set around this area, as stated for example by Deb in [K. Deb, J. Sundar, N. Udaya Bhaskara Rao, S. Chaudhuri, Reference point based multiobjective optimization using evolutionary algorithms, International Journal of Computational Intelligence Research, 2(3) (2006) 273–286]. In this paper, we propose a variation of the concept of Pareto dominance, called g-dominance, which is based on the information included in a reference point and designed to be used with any MO evolutionary method or any MO metaheuristic. This concept will let us approximate the efficient set around the area of the most preferred point without using any scalarizing function. On the other hand, we will show how it can be easily used with any MO evolutionary method or any MO metaheuristic (just changing the dominance concept) and, to exemplify its use, we will show some results with some state-of-the-art-methods and some test problems.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号