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671.
We show that with few exceptions every local isometric automorphism of the group algebra of a compact metric group is an isometric automorphism.
672.
Let K(n,r) denote the minimum cardinality of a binary covering code of length n and covering radius r. Constructions of covering codes give upper bounds on K(n,r). It is here shown how computer searches for covering codes can be sped up by requiring that the code has a given (not necessarily full) automorphism group. Tabu search is used to find orbits of words that lead to a covering. In particular, a code D found which proves K(13,1) 704, a new record. A direct construction of D given, and its full automorphism group is shown to be the general linear group GL(3,3). It is proved that D is a perfect dominating set (each word not in D is covered by exactly one word in D) and is a counterexample to the recent Uniformity Conjecture of Weichsel. 相似文献
673.
In this paper, an improved routing strategy is proposed for enhancing the traffic capacity of scale-free networks. Instead of using the information of degree and betweenness centrality, the new algorithm is derived on the basis of the expanding betweenness centrality of nodes, which gives an estimate of the traffic handled by the vertex for a certain route set. Since the nodes with large betweenness centrality are more susceptible to traffic congestion, the traffic can be improved by redistributing traffic loads from nodes with large betweenness centrality to nodes with small betweenness centrality in the process of computing the collective routing table. Comparing with results of previous routing strategies, it is shown that the present improved routing performs more effectively. 相似文献
674.
本文研究了基柱同构于2F4(q)的线传递的几乎单群.利用了有限线性空间上线传递的自同构群的经典结论,以及2F4(q)的阶和极大子群等性质,获得了点稳定子群和线稳定子群的分类. 相似文献
675.
Mariusz Grech 《Journal of Graph Theory》2011,66(4):303-318
In this article, we improve known results, and, with one exceptional case, prove that when k≥3, the direct product of the automorphism groups of graphs whose edges are colored using k colors, is itself the automorphism group of a graph whose edges are colored using k colors. We have handled the case k = 2 in an earlier article. We prove similar results for directed edge‐colored graphs. © 2010 Wiley Periodicals, Inc. J Graph Theory 66:303‐318, 2011 相似文献
676.
Gerard J. Chang 《Journal of Graph Theory》2011,68(4):323-325
The total relative displacement of a permutation f of vertices of a connected graph G is , where the sum is taken over all unordered pairs of distinct vertices of G. Let π(G) denote the smallest positive value of δf(G) among the n! permutations f. Aitken [J Combin Theory Series A 87 (1999), 1–21] proved that π(Pn) = 2n ? 4 for the n‐path Pn, which was conjectured by Chartrand et al. [Proceedings of the 1996 Eighth Quadrennial International Conference on Graph Theory, Combinatorics Algorithms, and Applications I, New Issues Press, Kalamazoo, 1999, pp. 181–192]. This article gives a short proof of the result. © 2011 Wiley Periodicals, Inc. J Graph Theory 68:323‐325, 2011 相似文献
677.
Every extended affine Lie algebra of type A
1 and nullity ν with extended affine root system R(A
1, S), where S is a semilattice in ℝ
ν
, can be constructed from a TKK Lie algebra T (J (S)) which is obtained from the Jordan algebra J (S) by the so-called Tits-Kantor-Koecher construction. In this article we consider the ℤ
n
-graded automorphism group of the TKK Lie algebra T (J (S)), where S is the “smallest” semilattice in Euclidean space ℝ
n
. 相似文献
678.
对单复变中的Schwarz引理与Schwarz-Pick引理在C~n中的超球上进行了推广.考虑C~n中单位球B_n上模小于1的全纯函数f(z),并在f(0)=0的条件下给出函数在原点的任意阶导数的估计.更进一步地,得到了B_n上模小于1的任意全纯函数在任意点的高阶导数的估计. 相似文献
679.
680.