In a previous paper (J. Comput. System Sci. 64 (2002) 519), the authors introduced the notion of hypertree decomposition and the corresponding concept of hypertree width and showed that the conjunctive queries whose hypergraphs have bounded hypertree width can be evaluated in polynomial time. Bounde
Marshals, monotone marshals, and hypertree-width
โ Scribed by Isolde Adler
- Publisher
- John Wiley and Sons
- Year
- 2004
- Tongue
- English
- Weight
- 193 KB
- Volume
- 47
- Category
- Article
- ISSN
- 0364-9024
No coin nor oath required. For personal study only.
โฆ Synopsis
Abstract
The treeโwidth of a hypergraph H equals one less than the number of cops necessary to catch the robber in the Monotone Robber and Cops Game played on H. Analogously, the hypertreeโwidth of a hypergraph is characterised by the Monotone Robber and Marshals Game. While the Robber and Cops Game and its monotone variant coincide, Gottlob, Leone and Scarcello stated the corresponding question for the Robber and Marshals Game as an open problem. We give a negative answer. Concerning the generalised hypertreeโwidth, our counterexamples show that it is neither characterised by the Robber and Marshals Game nor by its monotone variant. We conclude by resuming how these hypergraph invariants are related. ยฉ 2004 Wiley Periodicals, Inc. J Graph Theory 47: 275โ296 2004
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