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1.
步尚全 《数学学报》1995,38(1):86-90
本文证明了存在一具有解析RNP的Banaich空间X,存在X上的Jensen凸集C以及x∈C,使得X上支撑在C的Jensen边界点上的Jensen测度均不以x为重心.  相似文献   

2.
In this paper we prove that there are hypercyclic (n+1)-tuples of diagonal matrices on Cn and that there are no hypercyclic n-tuples of diagonalizable matrices on Cn. We use the last result to show that there are no hypercyclic subnormal tuples in infinite dimensions. We then show that on real Hilbert spaces there are tuples with somewhere dense orbits that are not dense, but we also give sufficient conditions on a tuple to insure that a somewhere dense orbit, on a real or complex space, must be dense.  相似文献   

3.
When there is a complete sufficient statistic for the nuisance parameter which depends on the parameter of interest then there are locally optimal unbiased estimating functions, but generally there is no globally optimal estimating function. We consider conditioning on the minimal sufficient statistic for the nuisance parameter and find the conditional linear optimal unbiased estimating function. Since the nuisance parameter is totally eliminated in the conditional model there is no intrinsic problem in setting up conditional tests of significance and confidence intervals. A compromise between conditional and unconditional optimum estimating functions is suggested. The techniques are illustrated on three examples including the well known common means problem. The proposed hypothesis testing and confidence interval procedures work reasonably well for the examples considered.  相似文献   

4.
While there has been considerable work over the years on multistage lot-sizing models, particularly in an MRP environment, there has been relatively little work on systems recognizing the WIP effects when there is gradual conversion of the components into the final product, as in production planning using the EPQ model for planning the final product. Here we consider lot-sizing planning for a two-stage system in which the final product is planned using an EPQ model with partial backordering and the production of the components is controlled using basic EPQ models without backordering.  相似文献   

5.
In this paper we discuss relations between symplectic forms and smooth structures on closed manifolds. Our main motivation is the problem if there exist symplectic structures on exotic tori. This is a symplectic generalization of a problem posed by Benson and Gordon. We give a short proof of the (known) positive answer to the original question of Benson and Gordon that there are no Kähler structures on exotic tori. We survey also other related results which give an evidence for the conjecture that there are no symplectic structures on exotic tori.  相似文献   

6.
史恩慧  周丽珍 《数学学报》2006,49(2):459-464
1990年,Kato证明了Dendrite上不存在可扩同胚.本文证明了Dendrite上不存在可扩Z2作用.该结果回答了作者所提的一个问题,也推广了Kato的上述结论.  相似文献   

7.
8.
该文研究了一类格点分形图 (格点巢分形 )上的渗流模型 ,证明了该模型没有临界现象 ,进一步给出一个指数衰减律 .同时 ,指出一般有限分岔图上的渗流模型没有临界现象  相似文献   

9.
In this paper, we prove that on every Finsler 2-dimensional sphere, either there exist infinitely many prime closed geodesics or there exist at least two irrationally elliptic prime closed geodesics.  相似文献   

10.
In this paper,we observe a special kind of continuous functions on graphs.By estimating the integrals of these functions,we prove that there are no sensitive commutative group actions on graphs.Furthermore,we consider a 1-dimensional continuum composed of a spiral curve and a circle and show that there exist sensitive homeomorphisms on it,which answers negatively a question proposed by Kato in 1993.  相似文献   

11.
证明了n-维广义超立方体网络Q(m1,m2,…,mn)中,任意两个节点x和y之间存在长度均不超过H(x,y)+2的m1+m2+…+mn-n条内点不交的路由,其中有H(x,y)条长度不超过H(x,y),此处H(x,y)表示x到y的汉明距离.并在此基础上讨论了广义超立方体网络的容错路由问题.证明了即使无效点很多,但只要存在某个(n-1)-维广义超子立方体中无效节点较少,则该n-维广义超立方体中的任意两个有效节点之间可以找到最优路由或接近最优路由的有效路由.  相似文献   

12.
Recently, there are extensive studies on perfect state transfer (PST for short) on graphs due to their significant applications in quantum information processing and quantum computations. However, there is not any general characterization of graphs that have PST in literature. In this paper, the authors present a depiction on weighted abelian Cayley graphs having PST. They give a unified approach to describe the periodicity and the existence of PST on some specific graphs.  相似文献   

13.
This work deals with catastrophe of a spherical cavity and cavitation of a spherical cavity for Hooke material with 1/2 Poisson's ratio. A nonlinear problem, which is the Cauchy traction problem, is solved analytically. The governing equations are written on the deformed region or on the present configuration. And the conditions are described on moving boundary. A closed form solution is found. Furthermore, a bifurcation solution in closed form is given from the trivial homogeneous solution of a solid sphere. The results indicate that there is a tangent bifurcation on the displacement-load curve for a sphere with a cavity. On the tangent bifurcation point, the cavity grows up suddenly, which is a kind of catastrophe. And there is a pitchfork bifurcation on the displacement-load curve for a solid sphere. On the pitchfork bifurcation point, there is a cavitation in the solid sphere.  相似文献   

14.
A chromatic-index-critical graphGonnvertices is non-trivial if it has at most Δ edges. We prove that there is no chromatic-index-critical graph of order 12, and that there are precisely two non-trivial chromatic-index-critical graphs on 11 vertices. Together with known results this implies that there are precisely three non-trivial chromatic-index-critical graphs of order ≤12.  相似文献   

15.
本文考虑光滑曲面片 M上的基本 Φr 形式及无穷小变形 Φ,推广了一些经典的结果 .主要有如下两个定理 :定理 A 若Φr=λΦ1或Φr+ 1=Φr 对某 r=2 ,3,…成立 ;或Φr=λΦq 对某 r>q≥ 1成立 ,则 M是全脐的或可展的 ,极小的 ,其中λ是 M上的函数 .定理 B 若Φ是无穷小Φr+ 1等距的 ( r>2 ) ,如果在 M上 :( a) K≠ 0 ,δK=0或 K >0 ,δH =0 ;( b)存在M上的函数λ,使δΦr=λΦr,则Φ也是无穷小Φr 等距的 .  相似文献   

16.
该文利用[1]中关于可反转映射的KAM定理,证明一定条件下R~3上的可反转映射在下动点附近存在不变锥面.并验证Fibonacci迹映射中存在这种不变锥面.  相似文献   

17.
Let X be a comPlex Banach space and let D be the open unit disc in the complex plane.We shall denote by H"(D, X) the Banach space consisting of all uniformly bounded X-vaued analytic functions defined on D equipped with the norm llflloo = suP lIf(z)Il. Az eDcomplex Banach space X is said to have the analytic Radon-NikOdym property if eachelemellt f E Hoo(D,X) has radial limits almost everywhere on the torus T = {e": 0 E[0, 2x]} (see [1]), this means that for almost all 0 C [0,27l, 9W…  相似文献   

18.
In pest control, there are only a few papers on mathematical models of the dynamics of microbial diseases. In this paper a model concerning biologically-based impulsive control strategy for pest control is formulated and analyzed. The paper shows that there exists a globally stable susceptible pest eradication periodic solution when the impulsive period is less than some critical value. Further, the conditions for the permanence of the system are given. In addition, there exists a unique positive periodic solution via bifurcation theory, which implies both the susceptible pest and the infective pest populations oscillate with a positive amplitude. In this case, the susceptible pest population is infected to the maximum extent while the infective pest population has little effect on the crops. When the unique positive periodic solution loses its stability, numerical simulation shows there is a characteristic sequence of bifurcations, leading to a chaotic dynamic, which implies that this model has more complex dynamics, including period-doubling bifurcation, chaos and strange attractors.  相似文献   

19.
提出了一种确定切换系统稳定性分析的方法.引入了两个相关的实例(非完整系统和约束摆)进行说明.用有限个模型的集合组成非线性模型,且切换序列可以是任意的.假定在切换瞬间状态不出现跳跃,并且不出现Zeno现象,即在每个有界时间段上,切换次数是有限的.在对所确定切换系统的分析中,应用了多次Liapunov函数,并证明了全局指数稳定性.系统的指数稳定性平衡关系到实际应用,因为这样的系统有着更强健的抗干扰能力.  相似文献   

20.
研究Poisson比为1/2的Hooke材料中,空穴的突变和萌生现象·求解一个球对称几何非线性弹性力学的移动边界(movingboundary)问题,空穴为球形,远离空穴处为三向均匀拉伸应力状态,在当前构形上列控制方程;在当前构形边界上列边界条件·找到了这个自由边界问题的封闭解并得到空穴半径趋于零时的叉型分岔解·计算结果显示,在位移_载荷曲线上存在一个切分岔型分岔点(或鞍结点型分岔点、极值型分岔点),这个分岔点说明在外力作用下空穴会发生突变,即突然“长大”;当球腔半径趋于零时,这个切分岔转化为叉型分岔(或分枝型分岔),这个叉型分岔可以解释实心球中的空穴萌生现象  相似文献   

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