Báo cáo toán học: "A Note on Obstructions to Clustered Planarity" pptx

... resulting in ten obstructions to clustered pla- narity [6]. the electronic journal of combinatorics 18 (2011), #P159 5 A Note on Obstructions to Clustered Planarity Jamie Sneddon Department of ... Obstructions to Clustered Planarity We use Theorem 1 to find the obstructions to clustered planarity. Note that all ss-planar digraphs are also clustered planar. We...

Ngày tải lên: 08/08/2014, 14:23

... Natural Science Foundation of China (11061012), the project supported by program to Sponsor Teams for Innovation in the Construction of Talent Highlands in Guangxi Institutions of Higher Learning ... becomes. By this argument, one should also expect to get stronger results if we use larger weights. And it would be of considerable interest to determine the optimal weights. On the other...

Ngày tải lên: 20/06/2014, 21:20

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... a maximal nonhamiltonian split gr aph. Since H 4,6 is nonhamiltonian, by Theorem 4 the graph H 4,6 [X, v ∗ 1 ]isnon- hamiltonian. Therefore, if T has a Hamilton cycle C then C must contain the edge ... both to the first question for all k ≥ 4 and to the second question for all k ≥ 5. We would like to note that there is an interesting discussion about the Burkard–Hammer condition in [9]...

Ngày tải lên: 06/08/2014, 05:20

... <k<7/4+. Note that 7/4isthethreshold of repetition 1 Thanks to Kirby Baker for the use of his software which allowed the author to make these discoveries concerning abcacb. A note on antichains ... to avoid than finite antichains! That is, to avoid a finite antichain over S it may be necessary to move to a larger alphabet, whereas this is not the case with infinite antic...

Ngày tải lên: 07/08/2014, 06:20

... 05E05. Notation Let P (n) denote the number of (unordered) partitions of n into positive integers, and let φ denote the Euler totient function. Let V be the standard n-dimensional representation of ... n ≤ 23. Note that D(n) appears to be close to E(n + 1). We don’t have any theoretical explanation of this observation. the electronic journal of combinatorics 7 (2000), #R6 8 Proposition...

Ngày tải lên: 07/08/2014, 06:20

... for a constant κ<2/3, then it outputs a cover graph whp. Note that the output graph will have whp girth equal to 4. On a related note we point to [8] which surveys constructions of non cover ... Combinatorica 11 (1991) 45-54. the electronic journal of combinatorics 7 (2000), #R19 9 [8] O. Pretzel, Orientations and Edge Functions on Graphs, in: A.D.Keedwell (ed.), Surveys in Com...

Ngày tải lên: 07/08/2014, 06:20

... information on Maple) implementation of the downhill simplex function optimization method (see [13] for a good description of the method and a C implementation) to the maximize the expression. This ... now consider an arbitrary term of the double sum that appears in (7) and examine for which values of r it converges to 0. If we find a condition on r that forces such a term to converg...

Ngày tải lên: 07/08/2014, 06:20