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限制边连通度是对传统边连通度的推广 ,而且是计算机互连网络容错性的一个重要度量 .本文考虑两类重要的网络模型———Kautz有向图K(d ,n)和Kautz无向图UK(d ,n)的限制边连通度λ′,并得到如下结果 :除了λ′(K( 2 ,1) )不存在外 ,均有λ′(K(d ,n) ) =2d-2 ;当d≥ 3 ,n≥ 3时 ,4d-5≤λ′(UK(d ,n) ) ≤ 4d -4 . 相似文献
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限制边连通度作为边连通度的推广,是计算机互连网络可靠性的一个重要度量.Superλ-′是比限制边连通度更精确的一个网络可靠性指标.一个图是Superλ-′的,如果它的任一最小限制边割都孤立一条有最小边度的边.本文考虑一类重要的网络模型-无向K autz图UK(d,n)的限制边连通度λ,′证明了当d 3,n 2时,λ(′UK(d,n))=4d-4,并进一步指出此时的UK(d,n)是Superλ-′的. 相似文献
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图的超常边连通度是图的边连通度概念的推广.对于n阶点可迁或正则边可迁的简单连通图来说,它的h阶超常边连通度λh一定存在(1≤h≤n/2).本文证明了当dr正则的n-阶点可迁简单连通图满足n≥6,d≥4且围长g≥5时,或d-正则的n-阶边可迁简单连通图满足n≥6,d≥4且围长g≥4时,对于任何的h1≤h≤min{g-1,n/2},λh达到其最大可能值,即λh=hd-2(h-1). 相似文献
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图的超常边连通度是图的边连通度概念的推广,对于n阶点可迁或正则边可迁的简单连通图来说,它的h阶超常边连通度λ_h一定存在(1≤h≤n/2)。本文证明了:当d_-正则的n_-阶点可迁简单连通图满足n≥6,d≥4且围长g≥5时,或d_-正则的n_-阶边可迁简单连通图满足n≥6,d≥4且围长g≥4时,对于任何的h:1≤h≤min{g-1,n/2},λ_h达到其最大可能值,即λ_h=hd-2(h-1)。 相似文献
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The h-super connectivity κh and the h-super edge-connectivity λh are more refined network reliability indices than the conneetivity and the edge-connectivity. This paper shows that for a connected balanced digraph D and its line digraph L, if D is optimally super edge-connected, then κ1(L) = 2λ1 (D), and that for a connected graph G and its line graph L, if one of κ1 (L) and λ(G) exists, then κ1(L) = λ2(G). This paper determines that κ1(B(d, n) is equal to 4d- 8 for n = 2 and d ≥ 4, and to 4d-4 for n ≥ 3 and d ≥ 3, and that κ1(K(d, n)) is equal to 4d- 4 for d 〉 2 and n ≥ 2 except K(2, 2). It then follows that B(d,n) and K(d, n) are both super connected for any d ≥ 2 and n ≥ 1. 相似文献
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图的限制性边连通度等于其最小边度的一个充分条件 总被引:6,自引:1,他引:5
设G是有限简单无向图.D,g和δ分别表示G的直径,围长和顶点最小度,本文证明,如果D≤g-2,且δ≥3,那么λ'=ξ,这里λ'=λ'(G)和ξ=ξ(G)分别表示G的限制性边连通度和最小边度,它在条件和结论两个方面都改进了已有的研究结果。 相似文献
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正则图的限制性边连通度 总被引:1,自引:0,他引:1
将连通图分离成阶至少为二的分支之并的边割称为限制性边割,最小限制性边割的阶称为限制性边连通度.
用λ′(G)表示限制性连通度,则λ′(G)≤ξ(G),其中ξ(G)表示最小边度.
如果上式等号成立,则称G是极大限制性边连通的. 本文证明了当k>|G|/2时,k正则图G是极大限制性边连通的,其中k≥2,
|G|≥4; k的下界在某种程度上是不可改进的. 相似文献
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设S是连通图G的一个边割.若G-S不包含孤立点,则称S是G的一个限制边割.图G的最小限制边割的边数称为G的限制边连通度,记为λ'(G).如果图G的限制边连通度等于其最小边度,则称图G是最优限制边连通的,简称λ'-最优的.进一步,如果图G的每个最小限制边割恰好分离出图G的一条边,则称图G是超级限制边连通的,简称超级-λ'的.设G是一个最小度δ(G)≥2的n≥4阶二部图,ξ(G)是G的最小边度.本文证明了(a)若ξ(G)≥(n/2-2)(1+1/δ(G)-1),则G是λ'-最优的;(b)若ξ(G)>(n/2-2)(1+1/δ(G)-1),则G是超级-λ'的,除非图G是K2,n-2,n≥6或是Cartesian积图Kn/4,n/4×K2,其中n≥8且n整除4.最后,论文举例说明该结果是最好可能的. 相似文献
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极小Cayley图的限制性边连通度 总被引:1,自引:0,他引:1
一个连通图X的边集的一个子集C称为一个限制性边割,如果它是一个边割,且X/C不含孤立点。X的限制性边连通度λ′(X)定义为所有限制性边割的最小基数。本文完全决定了极小Cayley图的限制性边连通度。 相似文献
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1.IntroductionAgraphG=(V,E)meansafinitegraphwithoutloopsandmultipleedgeswithvertexsetVandedgesetE,theclassicaledgeconnectivityA(G)ofGistheminimumsizeofasetUofedgessuchthatG--Uisdisconnected,andsuchasetUiscalledaoutsetofG.Notethatintheabovedefinition,absolutelynoconditionsorrestrictionsareimposedeitheronthecomponelltsofG--UoronthesetU.ThusitwouldseemnaturaltogeneralizetheconceptofedgeconnectivitybyintroducingsomeconditionsorrestrictionsonthecomponentsofG--Uand/orthesetU.Asageneralizatio… 相似文献
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本文推广了Branner-Hubbard-Yoccoz拼图技巧来研究偶四次多项式填充Julia集的连通性,得到类似Branner-Hubbard关于三次多项式的定理。 相似文献
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偶四次多项式Julia集的连通性 总被引:1,自引:0,他引:1
本文推广了Branner-Hubbard-Yoccoz拼图技巧来研究偶四次多项式填充Julia集的连通性,得到类似Branner-Hubbard关于三次多项式的定理. 相似文献
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Let G =(V, E) be a connected graph and m be a positive integer, the conditional edge connectivity λ_δ~m is the minimum cardinality of a set of edges,if it exists, whose deletion disconnects G and leaves each remaining component with minimum degree δ no less than m. This study shows that λ_δ~1(Q_(n,k)) = 2 n,λ_δ~2(Q_(n,k)) = 4 n-4(2 ≤ k ≤ n-1, n ≥ 3) for n-dimensional enhanced hypercube Q_(n,k). Meanwhile, another easy proof about λ_δ~2(Q_n) = 4 n-8, for n ≥ 3 is proposed. The results of enhanced hypercube include the cases of folded hypercube. 相似文献
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本文确定了一个有限群特征标环通过代数整数环扩张后素谱的结构,在此基础之上,利用与[1]中类似的方法证明了这个扩张后的特征标环素谱的连通性。同时还计算了有限群的复类函数空间的幂等元. 相似文献
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设 D=(V,A)是局部连通度至多是1的严格有向图,令 n 和 e(D)分别表示 D 的点数和弧数.本文证明:若 n≤7,则 e(D)≤2(n-1);若 n≥7,则 e(D)≤[(n~2)/4];并且给出极图的完全刻画. 相似文献
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Zhao Keyou 《数学年刊B辑(英文版)》1986,7(3):339-344
In this paper the author studies the controllability, reachability and strong connectivity of discrete-time linear systems with positively limited controls. Necessary
and sufficient conditions are given to test these properties for a single-input system. 相似文献
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ALTERING CONNECTIVITY WITH LARGE DEFORMATION MESH FOR LAGRANGIAN METHOD AND ITS APPLICATION IN MULTIPLE MATERIAL SIMULATION 下载免费PDF全文
A new approach for treating the mesh with Lagrangian scheme of finite volume method is presented. It has been proved that classical Lagrangian method is difficult to cope with large deformation in tracking material particles due to severe distortion of cells, and the changing connectivity of the mesh seems especially attractive for solving such issues. The mesh with large deformation based on computational geometry is optimized by using new method. This paper develops a processing system for arbitrary polygonal unstructured grid, the intelligent variable grid neighborhood technologies is utilized to improve the quality of mesh in calculation process, and arbitrary polygonal mesh is used in the Lagrangian finite volume scheme. The performance of the new method is demonstrated through series of numerical examples, and the simulation capability is efficiently presented in coping with the systems with large deformations. 相似文献