共查询到20条相似文献,搜索用时 125 毫秒
1.
The recent discovery of memristive neurodynamic systems holds great promise for realizing large‐scale nanoionic circuits. Development of pattern memory analysis for memristive neurodynamic systems poses several challenges. In this article, it shows that an n‐dimensional memristive neural networks with time‐varying delays can have 2n locally exponentially stable equilibria in the saturation region. In addition, local exponential stability of delayed memristive neural networks in any designated region is also characterized, which allows the locally exponentially stable equilibria to locate in the designated region. All of these criteria are very easy to be verified. Finally, the effectiveness of the results are illustrated by two numerical examples. © 2014 Wiley Periodicals, Inc. Complexity 21: 177–186, 2015 相似文献
2.
Shandelle M. Henson 《Journal of Difference Equations and Applications》2013,19(3):315-331
The local existence and local asymptotic stability of nontrivial p-periodic solutions of p-periodically forced discrete systems are proven using Liapunov-Schmidt methods. The periodic solutions bifurcate transcritically from the trivial solution at the critical value n=ncr of the bifurcation parameter with a typical exchange of stability. If the trivial solution loses (gains) stability as n is increased through ncr , then the periodic solutions on the nontrivial bifurcating branch are locally asymptotically stable if and only if they correspond to n>ncr (n ncr ). 相似文献
3.
Mei-Yue Jiang 《manuscripta mathematica》1994,85(1):307-321
The existence of periodic solutions to Hamiltonian systems on the symplectic manifold (T
2n, ω) is studied. We show that on a class of hypersurfaces in the torusT
2n there is a periodic solution, which generalizes the results due to Long and Zehnder.
Supported by NNSF of China 相似文献
4.
The following two theorems are proved: (1) the generator of an exponentially equicontinuousn-times integratedC-cosine function also generates an exponentially equicontinuous [(n+1)/2]-times integratedC-semigroup; (2) IfA and −A are generators of exponentially equicontinuousn-times integratedC-semigroups, thenA
2 generates an exponentially equicontinuousn-times integratedC-cosine function. 相似文献
5.
Zhenkun Huang Sannay Mohamad Chunhua Feng Guorong Cai 《Applied Mathematical Modelling》2010,34(1):80-91
This paper presents new dynamical behavior, i.e., the coexistence of 2N domains of attraction of N-dimensional nonautonomous neural networks with time-varying delays. By imposing some new assumptions on activation functions and system parameters, we construct 2N invariant basins for neural system and derive some criteria on the boundedness and exponential attractivity for each invariant basin. Particularly, when neural system degenerates into periodic case, we not only attain the coexistence of 2N periodic orbits in bounded invariant basins but also give their domains of attraction. Moreover, our results are suitable for autonomous neural systems. Our new results improve and generalize former ones. Finally, computer simulation is performed to illustrate the feasibility of our results. 相似文献
6.
Genadi Levin 《Israel Journal of Mathematics》2009,170(1):285-315
We prove a result about an extension of the multiplier of an attracting periodic orbit of a quadratic map as a function of
the parameter. This has applications to the problem of geometry of the Mandelbrot and Julia sets. In particular, we prove
that the size of p/q-limb of a hyperbolic component of the Mandelbrot set of period n is O(4
n
/p), and give an explicit condition on internal arguments under which the Julia set of corresponding (unique) infinitely renormalizable
quadratic polynomial is not locally connected.
In memory of my grandmother Esfir Garbuz 相似文献
7.
On the Construction of <Emphasis Type="Italic">p</Emphasis>-Harmonic Morphisms and Conformal Actions
Xiao Huan MO Li Bing HUANG Yuan Zheng ZHANG 《数学学报(英文版)》2007,23(8):1475-1484
We produce p-harmonic morphisms by conformal foliations and Clifford systems. First, we give a useful criterion for a foliation on an m-dimensional Riemannian manifold locally generated by conformal fields to produce p-harmonic morphisms. By using this criterion we manufacture conformal foliations, with codimension not equal to p, which are locally the fibres of p-harmonic morphisms. Then we give a new approach for the construction of p-harmonic morphisms from R^m/{0} to R^n. By the well-known representation of Clifford algebras, we find an abundance of the new 2/3 (m + 1)-harmonic morphism Ф: R^m/{0} → R^n where m = 2κδ(n - 1). 相似文献
8.
Jerzy Jezierski Wacław Marzantowicz 《Bulletin of the Brazilian Mathematical Society》2005,36(2):205-224
A well-known example, given by Shub, shows that for any |d| ≥ 2 there is a self-map of the sphere Sn, n ≥ 2, of degree d for which the set of non-wandering points consists of two points. It is natural to ask which additional
assumptions guarantee an infinite number of periodic points of such a map. In this paper we show that if a continuous map
f : Sn → Sn commutes with a free homeomorphism g : Sn → Sn of a finite order, then f has infinitely many minimal periods, and consequently infinitely many periodic points. In other words the assumption of the
symmetry of f originates a kind of chaos. We also give an estimate of the number of periodic points.
*Research supported by KBN grant nr 2 P03A 045 22. 相似文献
9.
10.
Antonio Tortora 《代数通讯》2013,41(2):431-438
For any integer n ≠ 0,1, a group G is said to be “n-Bell” if it satisfies the identity [x n ,y] = [x,y n ]. It is known that if G is an n-Bell group, then the factor group G/Z 2(G) has finite exponent dividing 12n 5(n ? 1)5. In this article we show that this bound can be improved. Moreover, we prove that every n-Bell group is n-nilpotent; consequently, using results of Baer on finite n-nilpotent groups, we give the structure of locally finite n-Bell groups. Finally, we are concerned with locally graded n-Bell groups for special values of n. 相似文献
11.
Vyacheslav S. Rychkov 《Mathematische Nachrichten》2001,224(1):145-180
Characterizations via convolutions with smooth compactly supported kernels and other distinguished properties of the weighted Besov–Lipschitz and Triebel–Lizorkin spaces on ℝn with weights that are locally in Ap but may grow or decrease exponentially at infinity are investigated. Square–function characterizations of the weighted Lp and Hardy spaces with the above class of weights are also obtained. A certain local variant of the Calderón reproducing formula is constructed and widely used in the proofs. 相似文献
12.
We consider the Turan n-dimensional extremum problem of finding the value of An(hB
n
) which is equal to the maximum zero Fourier coefficient
of periodic functions f supported in the Euclidean ball hB
n
of radius h, having nonnegative Fourier coefficients, and satisfying the condition f(0)= 1. This problem originates from applications to number theory. The case of A1([–h,h]) was studied by S. B. Stechkin. For An(hB
n
we obtain an asymptotic series as h 0 whose leading term is found by solving an n-dimensional extremum problem for entire functions of exponential type. 相似文献
13.
In this paper we consider multifacility location problems on tree networks. On general networks, these problems are usually
NP-hard. On tree networks, however, often polynomial time algorithms exist; e.g., for the median, center, centdian, or special
cases of the ordered median problem. We present an enhanced dynamic programming approach for the ordered median problem that
has a time complexity of just O(ps
2
n
6) for the absolute and O(ps
2
n
2) for the node restricted problem, improving on the previous results by a factor of O(n
3). (n and p being the number of nodes and new facilities, respectively, and s (≤n) a value specific for the ordered median problem.) The same reduction in complexity is achieved for the multifacility k-centrum problem leading to O(pk
2
n
4) (absolute) and O(pk
2
n
2) (node restricted) algorithms. 相似文献
14.
The main aim of the paper is Fredholm properties of a class of bounded linear operators acting on weighted Lebesgue spaces
on an infinite metric graph Γ which is periodic with respect to the action of the group
\mathbb Zn{{\mathbb {Z}}^n} . The operators under consideration are distinguished by their local behavior: they act as (Fourier) pseudodifferential operators
in the class OPS
0 on every open edge of the graph, and they can be represented as a matrix Mellin pseudodifferential operator on a neighborhood
of every vertex of Γ. We apply these results to study the Fredholm property of a class of singular integral operators and
of certain locally compact operators on graphs. 相似文献
15.
Mieczys?aw Borowiecki Piotr Borowiecki El?bieta Sidorowicz Zdzis?aw Skupień 《Czechoslovak Mathematical Journal》2010,60(2):571-587
A graph G is a locally k-tree graph if for any vertex v the subgraph induced by the neighbours of v is a k-tree, k ⩾ 0, where 0-tree is an edgeless graph, 1-tree is a tree. We characterize the minimum-size locally k-trees with n vertices. The minimum-size connected locally k-trees are simply (k + 1)-trees. For k ⩾ 1, we construct locally k-trees which are maximal with respect to the spanning subgraph relation. Consequently, the number
of edges in an n-vertex locally k-tree graph is between Ω(n) and O(n
2), where both bounds are asymptotically tight. In contrast, the number of edges in an n-vertex k-tree is always linear in n. 相似文献
16.
This paper studies a multicast problem arising in wavelength division multiplexing single-hop lightwave networks, as well as in Video-on-Demand systems. In this problem, the same message of duration Δ has to be transmitted to a set of n receivers which are not all available simultaneously. The receivers can be partitioned into subsets, each served by a different transmission, with the objective of minimizing their overall waiting cost. When there is a single data channel available for transmission, a dynamic programming algorithm is devised which finds an optimal solution in O(nlogn+min{n2,nΔ2}) time, improving over a previously known O(n3) time algorithm. When multiple data channels are available for transmission, an optimal O(n) time algorithm is proposed which finds an optimal solution if the message has constant transmission duration, whereas an NP-completeness proof is given if the message has arbitrary transmission duration. 相似文献
17.
Thomas A. Richmond 《Order》2013,30(2):487-496
We find all locally convex homogeneous topologies on (?, ≤?) and determine which of these have locally convex complements. Among the locally convex topologies on an n-point totally ordered set, each has a locally convex complement and, for n?≥?3, at least n???2 of them have 2 n???1 locally convex complements. For any infinite cardinal κ, totally ordered spaces of cardinality κ which have exactly 1, exactly κ, and exactly 2 κ locally convex complements are exhibited. 相似文献
18.
L. A. Kurdachenko 《Ukrainian Mathematical Journal》1990,42(3):303-307
The study of locally nilpotent groups with the weak minimality condition for normal subgroups, the min––n condition, is continued. The following results are obtained.THEOREM 1. A locally nilpotent group with the min––n condition is countable.THEOREM 2. If G is a locally nilpotent group with the min––n condition whose periodic part is nilpotent and the orders of the elements of the periodic part are bounded in the aggregate, then G=t(G)A, where the subgroup A is minimax.THEOREM 3. Suppose G is a locally nilpotent group with the min––n condition and T is its periodic part. If T is nilpotent and G/T is Abelian, then G=TA, where the subgroup A is minimax.Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 42, No. 3, pp. 340–346, March, 1990. 相似文献
19.
An (n+1, 1)-design D is locally extensible at a block B if D can be embedded in an (n+1, 1)-design having a block B
* of cardinality n+1 and such that BB
*. If D is embeddable in a finite projective plane of order n, then D is called globally extensible. In this paper, we investigate the asymptotic behaviour of locally extensible designs and Euclidean designs. We study the relationship between locally extensible and extensible designs and the uniqueness of such embeddings. It is shown that, for n, l and t sufficiently large, any (n+1, 1)-design which has minimum block length l and which is locally extensible at t of its blocks is globally extensible. 相似文献
20.
WANG Meng CHEN Jiecheng & FAN Dashan Department of Mathematics Zhejiang University 《中国科学A辑(英文版)》2006,49(1):98-108
We study certain square functions on product spaces Rn × Rm, whose integral kernels are obtained from kernels which are homogeneous in each factor Rn and Rm and locally in L(log L) away from Rn × {0} and {0} × Rm by means of polynomial distortions in the radial variable. As a model case, we obtain that the Marcinkiewicz integral operator is bounded on Lp(Rn × Rm)(P > 1) for Ω∈ e Llog L(Sn-1 × Sm-1) satisfying the cancellation condition. 相似文献