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91.
By constructing Liapunov functions and building a new inequality, we obtain two kinds of sufficient conditions for the existence and global exponential stability of almost periodic solution for a Hopfield-type neural networks subject to almost periodic external stimuli. In this paper, we assume that the network parameters vary almost periodically with time and we incorporate variable delays in the processing part of the network architectures. 相似文献
92.
Yan-Kui Song 《Acta Mathematica Hungarica》2006,111(3):213-220
Summary A subset Y of a space X is weakly almost Lindel?f in X if for every open cover U of X, there exists a countable subfamily V of U such that Y ⊆ comp (∩V ). We investigate the relationship between relatively weakly almost Lindel?f subsets and relatively almost Lindel?f
subsets, and also study various properties of relatively weakly almost Lindel?f subsets. 相似文献
93.
Petr Lachout 《Annals of Operations Research》2006,142(1):187-214
The paper deals with an epi-convergence of random real functions defined on a topological space. We follow the idea due to
Vogel (1994) to split the epi-convergence into the lower semicontinuous approximation and the epi-upper approximation and
localize them onto a given set. The approximations are shown to be connected to the miss- resp. hit-part of the ordinary Fell
topology on sets. We introduce two procedures, called “localization”, separately for the miss-topology and the hit-topology
on sets. Localization of the miss- resp. hit-part of the Fell topology on sets allows us to give a suggestion how to define
the approximations in probability and in distribution. It is shown in the paper that in case of the finite-dimensional Euclidean
space, the suggested approximations in probability coincide with the definition from Vogel and Lachout (2003).
The research has been partially supported by Deutsche Forschungsgemeinschaft under grant No. 436TSE113/40, by the Ministry
of Education, Youth and Sports of the Czech Republic under Project MSM 113200008 and by the Grant Agency of the Czech Republic
under grant No. 201/03/1027. 相似文献
94.
洪佳林 《新疆大学学报(理工版)》1990,7(3):28-30
本文推广了林振声关于 Hale 问题的解答,利用微分系统的指数型三分性给出了弱概周期微分系统中心积分流形的存在性定理. 相似文献
95.
Primo? Poto?nik 《Discrete Mathematics》2006,306(1):107-123
A graph is called almost self-complementary if it is isomorphic to one of its almost complements Xc-I, where Xc denotes the complement of X and I a perfect matching (1-factor) in Xc. Almost self-complementary circulant graphs were first studied by Dobson and Šajna [Almost self-complementary circulant graphs, Discrete Math. 278 (2004) 23-44]. In this paper we investigate some of the properties and constructions of general almost self-complementary graphs. In particular, we give necessary and sufficient conditions on the order of an almost self-complementary regular graph, and construct infinite families of almost self-complementary regular graphs, almost self-complementary vertex-transitive graphs, and non-cyclically almost self-complementary circulant graphs. 相似文献
96.
We prove the existence of infinite subgroups with nontrivial locally finite radicals and of locally finite subgroups in the groups with almost finite almost solvable elements of prime orders and in the groups with generally finite elements. 相似文献
97.
Fazilet Erkekog˜lu 《Mathematical Physics, Analysis and Geometry》2006,8(4):361-388
The geometry of almost complex manifolds with degenerate indefinite Hermitian metrics is studied. 相似文献
98.
设(S,X)为数域K上以σ-有限测度空间(Ω,A,μ)为基的完备的RIP-模,而且α:S×S→L(μ,K)满足如下条件:(A)存在ξ∈L (μ),使得a(p,q)ξ·X~p·X~q,p,q∈S;(B)a是coercive(即,存在η∈L (μ),使得a(p,p)η·X~p2,p∈S且μ({ωη(ω)=0})=0);(C)对每个q∈S,a(·,q):S→L(μ,K)是模同态,且对每个p∈S,a(p,ξq1 ηq2)=ξ-a(p,q1) η-a(p,q2),q1,q2∈S及ξ,η∈L(μ,K).则存在唯一的连续模同态A:S→S使A-1存在且μ-a.s.有界,还满足:(1)a(p,q)=XA(p),q,p,q∈S;(2)X~A-1(p)1ηX~p,p∈S. 相似文献
99.
Xiang Hongjun Wang Jinhua Chen Anping 《Annals of Differential Equations》2005,21(4):604-615
In this paper, a class of two-dimensional shunting inhibitory cellular neural networks with distributed delays and variable coefficients system is studied. By using the Schauder's fixed point theorem and Lyapunov function, we obtain some sufficient conditions about the existence and attractivity of almost periodic solutions to the above system, and all its solutions converge to such almost periodic solution. An example is given to illustrate that the conditions of our results are feasible. 相似文献
100.
Ushangi Goginava 《Journal of Mathematical Analysis and Applications》2003,287(1):90-100
We prove that for the N-dimensional Walsh-Fourier series the maximal operator of the Marcinkiewicz means is of weak type (1,1). Moreover, the Marcinkiewicz means σnf of the function f∈L1 converge a.e. to f as n→∞. 相似文献