Báo cáo toán học: "Graphs with many copies of a given subgraph" ppt

... most graphs on n vertices contain substantially many copies of any fixed graph, but contain no complete bipartite subgraphs with both parts larger than C log n, for some C > 0, independent of n. Hence, ... graph of order 2; - K 2 (s, t) for the complete bipartite graph with parts of size s and t; - f| X for the restriction of a map f to a set X. Specific notation Suppos...

Ngày tải lên: 07/08/2014, 15:23

... coverings of these gives infinitely many hypermaps of type (l, m, n) and genus g  3. In particular, taking m = 2, if we can construct infinitely many planar maps of a given type, each with at least ... construct a tessellation D k of a closed disc D, with boundary type k (4) . We achieve that by starting with a square, regarded as a bipartite map on D with one f...

Ngày tải lên: 08/08/2014, 12:23

... dense random graph. The notion of a t-stable set is a generalisation of the notion of a stable set. Recall that a set of vertices S of a graph G is stable if no two of its vertices are adjacent. ... (B) We treat this case similarly. We consider an auxiliary bipartite graph as above. Let c ∈ S 2m (t, k) be a configuration of balls 1, . . . , 2m. Since there are at most...

Ngày tải lên: 08/08/2014, 12:22

... & Software Engineering University of Western Australia Nedlands WA 6009, Australia gordon@csse.uwa.edu.au Submitted: Apr 18, 2007; Accepted: Aug 22, 2007; Published: Aug 31, 2007 Mathematics ... removal leaves more than |S| components. This suggests that maybe it is the toughness of hamiltonian graphs (rather than the actual cycle itself) that is important, and along these lines Dong...

Ngày tải lên: 07/08/2014, 13:21

... corollary. Corollary 4. A tree G has greatest maximum eigenvalue in the class of all trees with n vertices and k leaves if and only if it is a star with paths of almost the same lengths attached ... call a connected graph that has a BFD-ordering of its vertices a BFD-graph. Every graph has for each of its vertices v an ordering with root v that satisfies (B1). This can...

Ngày tải lên: 07/08/2014, 21:20

... K 3 by attaching ex aclty one path (o f arbitrary length) to each of its vertices. Hasegawa and Saito [4] asked for a characterisation of all graphs with four boundary vertices. The aim of the ... with exactly three b oundary vertices. Attaching a path P to a vertex v of a graph G means taking the disjoint union of G and P and identifying v with an end-vertex of P ....

Ngày tải lên: 08/08/2014, 12:23

... Proceedings of the 40th Annual Meeting of the ACL. Michael Collins, Jan Hajic, Lance Ramshaw, and Christoph Tillmann. 1999. A Statistical Parser for Czech. In Pro- ceedings of the 37th Annual Meeting of ... the ACL. Michael Collins. 1999. Head-Driven Statistical Models for Natural Language Parsing. Ph.D. thesis, University of Pennsylvania. Julia Hockenmaier and Mark Steedman. 200...

Ngày tải lên: 20/02/2014, 16:20

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Ngày tải lên: 05/08/2014, 10:20

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Ngày tải lên: 05/08/2014, 15:20

... probability that two fixed edges (a i ,a j )and (a k ,a l ) are D π -bad. Consider first the case where (a i ,a j )and (a k ,a l ) share an endpoint, say a k = a i .Sinceπis random, the probability that ... probability that (a i ,a j )and (a i ,a l ) appear in the same member of D π is exactly h−2 r−2 .Toseethis,fixπ (a i ) and π (a j ), and let Q denote the unique memb...

Ngày tải lên: 07/08/2014, 06:20