| Project/Area Number |
24500007
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Fundamental theory of informatics
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| Research Institution | Gunma University |
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Principal Investigator |
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| Project Period (FY) |
2012-04-01 – 2016-03-31
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| Project Status |
Completed (Fiscal Year 2015)
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| Budget Amount *help |
¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
Fiscal Year 2014: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2013: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2012: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
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| Keywords | グラフパラメータ / 近似困難性 / Small Set Expansion 予想 / rank-width / clique-width / boolean-width / SSE予想 / vertex boundary-width / carving-width / 定数近似困難性 / Path-Distance-Width / Tangle / 極小セパレータ / minimal separator / unit disk graph |
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| Outline of Final Research Achievements |
The research shows that there are no polynomial time approximation algorithms with constant performance ratios for several graph width parameters such as rank-width, clique-width, carving-width, and boolean-width under Small Set Expansion conjecture. The inapproximability of path-distance-width, which was one of targets of the research, could not be clarified, but the inapproximability of maximum induced matching-width was serendipitously shown.
We also obtained the following two results as a by-product: One is some result on an infinite hierarchy of thin strip graphs, the other is a result on algebraic property of tangle (a dual notion of branch-width).
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