New upper bounds on the decomposability of planar graphs and fixed parameter algorithms
It is known that a planar graph on n vertices has branch-width/tree-width bounded by alphasqrt{n}. In many algorithmic applications it is useful to have a small bound on the constant alpha. We give a proof of the best, so far, upper bound for the constant alpha. In particular, for the case of tree-w...
| Authors: | ; |
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| Format: | Report |
| Publication date: | 2002 |
| Country: | España |
| Institution: | Universitat Politècnica de Catalunya (UPC) |
| Repository: | UPCommons. Portal del coneixement obert de la UPC |
| Language: | English |
| OAI Identifier: | oai:upcommons.upc.edu:2117/97430 |
| Online Access: | https://hdl.handle.net/2117/97430 |
| Access Level: | Open access |
| Keyword: | Planar graphs Decomposability Fixed parameter algorithms Tree-width Branch-width Separation theorems Vertex cover Dominating set Àrees temàtiques de la UPC::Informàtica |
| Summary: | It is known that a planar graph on n vertices has branch-width/tree-width bounded by alphasqrt{n}. In many algorithmic applications it is useful to have a small bound on the constant alpha. We give a proof of the best, so far, upper bound for the constant alpha. In particular, for the case of tree-width, alpha<3.182 and for the case of branch-width, alpha<2.122. Our proof is based on the planar separation theorem of Alon, Seymour & Thomas and some min-max theorem of the graph minors series. Based on these bounds we introduce a new method for solving different fixed parameter problems on planar graphs. We prove that our method provides the best so far exponential speed-up for fundamental problems on planar graphs like Vertex Cover, Dominating Set, Independent Set and many others. |
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