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1.
关于k—复盖图的几个条件   总被引:2,自引:1,他引:1  
设G是一个图,k为正整数,图G的一个k-正则支撑子图F称做图G的一个k-因子,若图G的每一条边e都属于G的一个k-因子,则称G是一个k-复盖图,本文给出了一个图G是k的复盖图的几个充分条件。  相似文献   

2.
设G是一个图,k为正整数.图G的一个k-正则支撑子图F称做图G的一个k-因子.若图G的每一条边e都属于G的一个k-因子,则称G是一个k-复盖图.本文给出了一个图G是k-复盖图的几个充分条件.  相似文献   

3.
度量空间的k—映射像   总被引:3,自引:3,他引:0  
刘川 《数学杂志》1994,14(2):233-236
E.Halfar([6]引入了k-映射概念,本文给出了度量空间k-映像的一个内在刻划,并由此得到一些度量化定理。  相似文献   

4.
恽自求 《数学进展》2000,29(3):223-226
本文给出了具有局部可数闭k-网的kr-空间成为k-空间的一个充要条件,此结果给林寿提出的问题作了一个回答。  相似文献   

5.
Banach空间上范数的各种k光滑性   总被引:8,自引:0,他引:8  
本文中,作者提出了k很光滑的概念,并研究了它和k光滑,弱Hahn-Banach光滑以及RNP之间的关系;还讨论了k光滑性和k强光滑性(kSS)的一些等价条件。  相似文献   

6.
完全k凸与局部完全k凸的关系   总被引:3,自引:0,他引:3  
王建华  王慕三 《数学杂志》1993,13(4):541-546
本文讨论了完全k凸与局部完全k凸之间的关系,它包含了Polak和Sims的结果。此外我们还给出局部一致凸空间的两个新特征,这些特征刻划了LUR,L-kR和Lk-UR之间的关系。  相似文献   

7.
局部k-一致凸空间的对偶空间   总被引:3,自引:0,他引:3  
本文证明了若Banach空间X是局部k-一致凸的,则对每个x∈S(X),f∈Σ(x)是X*的k-强光滑点,并得到局部k-一致凸空间的几个性质.  相似文献   

8.
邓起荣  陈建宝 《数学学报》1998,41(2):385-392
考虑多元线性模型Y~N(XΘ,σ2ImV),和SXΘ的估计问题,取损失函数为(σ-SXΘ)′(δ-SXΘ),本文定义所谓的k-容许性和Φ(k)-容许性.本文在一定条件下得到了SXΘ的线性估计LY+D在一切估计类中k-容许和Φ(k)-容许的充要条件.一般情况下得到了充分条件和必要条件.  相似文献   

9.
J.Csirik与D.S.Johnson针对带k-箱限制的在线装箱问题提出了四种装入和关闭法则,并利用这些法则给出了四种相应的算法.其中BBFk,NkF和ABFk算法的紧界在文[1-3]中分别进行了很好的研究.但对算法AFBk来讲,其紧界仍是一个公开问题.本文给出了AFBk算法性能比的一个上界,即.同时,本文提出了一个新的关闭法则,对AFBk算法进行了修改,使修改后的算法AFBk的性能比不超过1.7(k3)  相似文献   

10.
关于(X⊕Y)_1的凸性   总被引:1,自引:0,他引:1  
本文绘出k-严格凸、(局部)k一致圆定义的几个等价形式.利用等价形式,讨论了(X(X)1的k-严格凸及(局部)k一致圆性.  相似文献   

11.
Varieties of associative algebras over a field of characteristic zero are considered. Belov recently proved that, in any variety of this kind, the Hilbert series of a relatively free algebra of finite rank is rational. At the same time, for three important varieties, namely, those of algebras with zero multiplication, of commutative algebras, and of all associative algebras, a stronger assertion holds: for these varieties, formulas that rationally express the Hilbert series of the free product algebra via the Hilbert series of the factors are well known. In the paper, a system of counterexamples is presented which shows that there is no formula of this kind in any other variety, even in the case of two factors one of which is a free algebra. However, if we restrict ourselves to the class of graded PI-algebras generated by their components of degree one, then there exist infinitely many varieties for each of which a similar formula is valid. Translated fromMatematicheskie Zametki, Vol. 65, No. 5, pp. 693–702, May, 1999.  相似文献   

12.
A generalization of both the hierarchical product and the Cartesian product of graphs is introduced and some of its properties are studied. We call it the generalized hierarchical product. In fact, the obtained graphs turn out to be subgraphs of the Cartesian product of the corresponding factors. Thus, some well-known properties of this product, such as a good connectivity, reduced mean distance, radius and diameter, simple routing algorithms and some optimal communication protocols, are inherited by the generalized hierarchical product. Besides some of these properties, in this paper we study the spectrum, the existence of Hamiltonian cycles, the chromatic number and index, and the connectivity of the generalized hierarchical product.  相似文献   

13.
14.
Covering-based rough sets,as a technique of granular computing,can be a useful tool for dealing with inexact,uncertain or vague knowledge in information systems.Matroids generalize linear independence in vector spaces,graph theory and provide well established platforms for greedy algorithm design.In this paper,we construct three types of matroidal structures of covering-based rough sets.Moreover,through these three types of matroids,we study the relationships among these matroids induced by six types of covering-based upper approximation operators.First,we construct three families of sets by indiscernible neighborhoods,neighborhoods and close friends,respectively.Moreover,we prove that they satisfy independent set axioms of matroids.In this way,three types of matroidal structures of covering-based rough sets are constructed.Secondly,we study some characteristics of the three types of matroid,such as dependent sets,circuits,rank function and closure.Finally,by comparing independent sets,we study relationships among these matroids induced by six types of covering-based upper approximation operators.  相似文献   

15.
A survey of the literature and state of the art of the mechanical aspects of delaminations in laminate composite structures is presented. Surface and internal delaminations of various origin, shape, and location are discussed. The origination, stability, and postcritical behavior of delaminations under quasi-static, cyclic, and dynamic loads are analyzed. Some problems for further investigations are discussed.  相似文献   

16.
Based on a classification of artificial societies and the identification of four different types of stakeholders in such societies, we investigate the potential of norm-governed behavior in different types of artificial societies. The basis of the analysis is the preferences of the stakeholders and how they influence the state of the society. A general conclusion drawn is that the more open a society is the more it has to rely on agent owners and designers to achieve norm-governed behavior, whereas in more closed societies the environment designers and owners may control the degree of norm-governed behavior. Paul Davidsson is professor at the Department of Systems and Software Engineering, School of Engineering, Blekinge Institute of Technology, Sweden. He received his Ph.D. in Computer Science in 1996 from Lund University, Sweden. His research interests include the theory and application of multi-agent systems, autonomous agents, and machine learning. Application areas include logistics, transport systems, district heating systems, building automation, and telecommunications systems. The results of this work have been reported in more than 75 peer-reviewed scientific articles published in international journals and conference proceedings. Moreover, he has been the co-editor of three books on Multi Agent Based Simulation and member of program committees of numerous international conferences, such as the International Joint Conference on Autonomous Agents and Multi-Agent Systems Stefan Johansson is an assistant professor at Department of Systems and Software Engineering, Blekinge Institute of Technology, Sweden, where he also finished his PhD in 2002. The main research areas cover coordination issues in multi-agent systems and theories of autonomous agents. Applications of special interests are agents in game ai, robotics, telecommunication networks. On his list of publications are more than 35 peer-reviewed papers published in conference proceedings and scientific journals in the areas of agents, ai, robotics and games. He has also been a member of a variety of programme committees of scientific conferences, including e.g. Intelligent Agent Technology.  相似文献   

17.
Discussed are some geometric aspects of the phase space formalism in quantum mechanics in the sense of Weyl, Wigner, Moyal, and Ville. We analyze the relationship between this formalism and geometry of the Galilei group, classical momentum mapping, theory of unitary projective representations of groups, and theory of groups algebras. Later on, we present some generalization to quantum mechanics on locally compact Abelian groups. It is based on Pontryagin duality. Indicated are certain physical aspects in quantum dynamics of crystal lattices, including the phenomenon of ‘Umklapp–Prozessen’. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

18.
We suggest a generalisation of the convex-hull method, or ‘DEA’ approach, for estimating the boundary or frontier of the support of a point cloud. Figuratively, our method involves rolling a ball around the cloud, and using the equilibrium positions of the ball to define an estimator of the envelope of the point cloud. Constructively, we use these ideas to remove lines from a triangulation of the points, and thereby compute a generalised form of a convex hull. The radius of the ball acts as a smoothing parameter, with the convex-hull estimator being obtained by taking the radius to be infinite. Unlike the convex-hull approach, however, our method applies to quite general frontiers, which may be neither convex nor concave. It brings to these contexts the attractive features of the convex hull: simplicity of concept, rotation-invariance, and ready extension to higher dimensions. It admits bias corrections, which we describe and illustrate through implementation.  相似文献   

19.
彭忠益  王艳 《运筹与管理》2020,29(7):144-155
定量的评判城市老旧居住小区整体交通环境质量并进而科学有效的提出老旧小区交通环境更新与改善措施,对城市老旧居住小区交通环境进行了调查,明确了老旧居住小区存在的突出交通问题,并提出了城市老旧居住小区交通环境评价的指标体系,包括行人跨路出行指数、无人行道路段长度占比、停车泊位供需比、路内非法停车占比、平均停车步行距离、泊位数量户数比、人均步行空间、无障碍通道、盲道设置比例、非机动车泊位供需比、地面停放车辆数小区面积比、外部穿行交通周转量小区面积比等。并给出了具体指标的计算方法与获得办法。以长沙市四个典型老旧居住小区为例,对评价方法进行了论证,并得到城市老旧居住小区存在的一般问题,包括人车混杂、人车交织现象严重,停车泊位短缺、车辆乱停乱放,交通设施、特别是弱势群体交通设施缺乏。给出的评价指标、评价方法与结论可为城市老旧小区改造更新,特别是其中很重要的交通环境更新提供决策依据。  相似文献   

20.
We study the existence, uniqueness and asymptotic behavior, as well as the stability of a special kind of traveling wave solutions for competitive PDE systems involving intrinsic growth, competition, crowding effects and diffusion. The traveling waves are exclusive in the sense that as the variable goes to positive or negative infinity, different species are close to extinction or carrying capacity. We perform an appropriate affine transformation of the traveling wave equations into monotone form and construct appropriate upper and lower solutions. By this means, we reduce the existence proof to application of well-known theory about monotone traveling wave systems (cf. [A. Leung, Systems of Nonlinear Partial Differential Equations: Applications to Biology and Engineering, MIA, Kluwer, Boston, 1989; J. Wu, X. Zou, Traveling wave fronts of reaction-diffusion systems with delay, J. Dynam. Differential Equations 13 (2001) 651-687] and [I. Volpert, V. Volpert, V. Volpert, Traveling Wave Solutions of Parabolic Systems, Transl. Math. Monogr., vol. 140, Amer. Math. Soc., Providence, RI, 1994]). Then, by using spectral analysis of the linearization over the profile, we prove the orbital stability of the traveling wave in some Banach spaces with exponentially weighted norm. Furthermore, we show that the introduction of some weight is necessary in the sense that, in general, traveling wave solutions with initial perturbations in the (unweighted) space C0 are unstable (cf. [I. Volpert, V. Volpert, V. Volpert, Traveling Wave Solutions of Parabolic Systems, Transl. Math. Monogr., vol. 140, Amer. Math. Soc., Providence, RI, 1994] and [D. Henry, Geometric Theory of Semilinear Parabolic Equations, Lecture Notes in Math., vol. 840, Springer-Verlag, New York, 1981]).  相似文献   

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