Bipartite dimension and Wikipedia:Featured list candidates/backlog/items: Difference between pages
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In the mathematical field of [[graph theory]], the '''bipartite dimension''' of an [[graph]] G=(V,E) is the minimum number of [[biclique]]s, that is, complete bipartite subgraphs, needed to [[covering (graph theory)|cover]] all edges in E. A collection of bicliques covering all edges in G is called a '''biclique edge cover''', or sometimes '''biclique cover'''. The bipartite dimension of G is often denoted by the symbol d(G). |
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* [[Wikipedia:Featured list candidates/List of Bleach episodes (season 8)|List of Bleach episodes (season 8)]] |
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==Bipartite dimension of some special graphs== |
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* [[Wikipedia:Featured list candidates/The O.C. (season 3)|The O.C. (season 3)]] |
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Fishburn and Hammer determine the bipartite dimension for some special graphs. For example, the path <math>P_n</math> |
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* [[Wikipedia:Featured list candidates/List of Bleach episodes (season 5)|List of Bleach episodes (season 5)]] |
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has <math>d(P_n) = \lfloor n/2 \rfloor</math>, the cycle <math>C_n</math> has <math>d(C_n)=\lceil n/2\rceil</math>, |
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* [[Wikipedia:Featured list candidates/List of universities in Ontario|List of universities in Ontario]] |
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and the complete graph <math>K_n</math> has <math>d(K_n) = \lceil\log n \rceil</math>. |
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* [[Wikipedia:Featured list candidates/List of awards and nominations received by The White Stripes|List of awards and nominations received by The White Stripes]] |
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* [[Wikipedia:Featured list candidates/Timeline of the 2006 Pacific hurricane season|Timeline of the 2006 Pacific hurricane season]] |
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==Computational complexity== |
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* [[Wikipedia:Featured list candidates/List of number-one Billboard Top Latin Albums of 2003|List of number-one Billboard Top Latin Albums of 2003]] |
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Determining d(G) is an [[optimization problem]]. The [[decision problem]] for bipartite dimension can be phrased as: |
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* [[Wikipedia:Featured list candidates/List of Bleach episodes (season 4)|List of Bleach episodes (season 4)]] |
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* [[Wikipedia:Featured list candidates/List of Brazilian states by Human Development Index|List of Brazilian states by Human Development Index]] |
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:INSTANCE: A graph <math>G=(V,E)</math> and a positive integer <math>k</math>. |
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:QUESTION: Does G admit a biclique edge cover containing at most <math>k</math> bicliques? |
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* [[Wikipedia:Featured list candidates/Alabama Crimson Tide football seasons|Alabama Crimson Tide football seasons]] |
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* [[Wikipedia:Featured list candidates/Arizona Diamondbacks seasons|Arizona Diamondbacks seasons]] |
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This problem is [[NP-complete]], even for [[bipartite graph]]s, as proved by Orlin. It appears as problem '''GT18''' in |
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* [[Wikipedia:Featured list candidates/List of D.Gray-man chapters|List of D.Gray-man chapters]] |
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Garey and Johnson's classical book on NP-completeness. This decision problem is a rather straightforward reformulation of |
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* [[Wikipedia:Featured list candidates/Mark of the Year|Mark of the Year]] |
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another decision problem on families of finite sets, the ''set basis problem'', proved |
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* [[Wikipedia:Featured list candidates/List of D.Gray-man episodes|List of D.Gray-man episodes]] |
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to be NP-complete earlier by Stockmeyer, and appearing as problem '''SP7''' in Garey and Johnson's book. |
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* [[Wikipedia:Featured list candidates/List of universities in Quebec|List of universities in Quebec]] |
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* [[Wikipedia:Featured list candidates/List of universities in British Columbia|List of universities in British Columbia]] |
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:INSTANCE: A collection of finite sets <math>S_1,\ldots,S_n</math> and a positive integer <math>k</math>. |
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* [[Wikipedia:Featured list candidates/List of awards and nominations received by Justice|List of awards and nominations received by Justice]] |
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:QUESTION: Can we choose at most <math>k</math> subsets such that their union equals <math>\bigcup_{i=1}^n S_i</math>, the union of all <math>S_i</math>? |
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* [[Wikipedia:Featured list candidates/List of awards and nominations received by Blink-182|List of awards and nominations received by Blink-182]] |
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* [[Wikipedia:Featured list candidates/List of S.H.E awards|List of S.H.E awards]] |
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To transform a bipartite graph <math>G=(U,V,E)</math> into an instance of the latter problem, simply take |
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<math>U = \bigcup_{i=1}^n S_i</math>, <math>V=\{S_1,\ldots, S_n\}</math>, |
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and <math> \{\{u,S_i\} \mid u \in S_i\}</math> as edge set. The converse direction is similar. |
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==References== |
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* P. C. Fishburn and P. L. Hammer. Bipartite dimensions and bipartite degrees of graphs. ''Discrete Mathematics'', 160:127-148, 1996 |
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* M. R. Garey and D. S. Johnson. ''[[Computers and Intractability: A Guide to the Theory of NP-Completeness]]''. Freeman, 1979. |
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* S. Monson, N. Pullman, and R. Rees: A survey of clique and biclique coverings and factorizations of (0,1)-matrices. ''Bulletin of the ICA'', vol 14, pp. 17--86, 1995. |
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* J. Orlin. Contentment in Graph Theory: Covering Graphs with Cliques. ''Indagationes Mathematicae'', 80:406–424, 1977. |
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* Larry J. Stockmeyer. The set basis problem is NP-complete. Technical Report RC-5431, IBM, 1975. |
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==See also== |
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[[List of NP-complete problems]] |
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==External Links== |
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[http://11011110.livejournal.com/134829.html blog entry about bipartite dimension by David Eppstein] |
Revision as of 21:53, 10 October 2008
- List of Bleach episodes (season 8)
- The O.C. (season 3)
- List of Bleach episodes (season 5)
- List of universities in Ontario
- List of awards and nominations received by The White Stripes
- Timeline of the 2006 Pacific hurricane season
- List of number-one Billboard Top Latin Albums of 2003
- List of Bleach episodes (season 4)
- List of Brazilian states by Human Development Index
- Alabama Crimson Tide football seasons
- Arizona Diamondbacks seasons
- List of D.Gray-man chapters
- Mark of the Year
- List of D.Gray-man episodes
- List of universities in Quebec
- List of universities in British Columbia
- List of awards and nominations received by Justice
- List of awards and nominations received by Blink-182
- List of S.H.E awards