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131.
Norbert Hegyvári 《Journal of Combinatorial Theory, Series A》2008,115(2):354-360
Given subset E of natural numbers FS(E) is defined as the collection of all sums of elements of finite subsets of E and any translation of FS(E) is said to be Hilbert cube. We can define the multiplicative analog of Hilbert cube as well. E.G. Strauss proved that for every ε>0 there exists a sequence with density >1−ε which does not contain an infinite Hilbert cube. On the other hand, Nathanson showed that any set of density 1 contains an infinite Hilbert cube. In the present note we estimate the density of Hilbert cubes which can be found avoiding sufficiently sparse (in particular, zero density) sequences. As a consequence we derive a result in which we ensure a dense additive Hilbert cube which avoids a multiplicative one. 相似文献
132.
Sergei Ovchinnikov 《Discrete Applied Mathematics》2008,156(8):1197-1219
In this paper we develop a representational approach to media theory. We construct representations of media by well-graded families of sets and partial cubes and establish the uniqueness of these representations. Two particular examples of media are also described in detail. 相似文献
133.
Necessary conditions for the complete graph on n vertices to have a decomposition into 5‐cubes are that 5 divides n ? 1 and 80 divides n(n ? 1)/2. These are known to be sufficient when n is odd. We prove them also sufficient for n even, thus completing the spectrum problem for the 5‐cube and lending further weight to a long‐standing conjecture of Kotzig. © 2005 Wiley Periodicals, Inc. J Combin Designs 14: 159–166, 2006 相似文献
134.
135.
136.
Jing XU LMAM School of Mathematical Sciences Peking University Beijing China 《中国科学A辑(英文版)》2007,50(12):1673-1679
In this paper we give a classification of the orientable regular embeddings of Q_n for n=2m with m odd.Actually we prove that the known examples given by Kwon are the only regular maps of Q_n when n=2m (m odd). 相似文献
137.
Topological properties of fuzzy numbers 总被引:9,自引:0,他引:9
138.
Peter Matthews 《Journal of Theoretical Probability》1989,2(1):129-146
Some properties of the set of vertices not visited by a random walk on the cube are considered. The asymptotic distribution of the first timeQ this set is empty is derived. The distribution of the number of vertices not visited is found for times nearEQ. Next the first time all unvisited vertices are at least some distanced apart is explored. Finally the expected time taken by the path to come within a distanced of all points is calculated. These results are compared to similar results for random allocations. 相似文献
139.
M-连续格到Hilbert方体的嵌入 总被引:2,自引:0,他引:2
本文主要讨论M-连续格到Hilbert方体的嵌入问题.我们建立了M-连续格的次直积表示理论,推广并统一了Raney,Bruns,Lawson,Bandelt和Erne等人的相应工作.Renay与Bruns的经典方法是建立在对相应的弱辅助关系的极大完备链作深入分析之上的,富于技巧性,且有局限性.与之相比,本文所使用的方体则相当朴素而自然,但却能处理更为广泛的情形. 相似文献
140.
Ghislain Jaudon 《Geometriae Dedicata》2008,135(1):23-27
By using the links between generalized roundness, negative type inequalities and equivariant Hilbert space compressions, we
obtain that the generalized roundness of the usual Cayley graph of finitely generated free groups and free abelian groups
of rank ≥ 2 equals 1. This answers a question of J-F. Lafont and S. Prassidis.
相似文献