The complexity of the matroid–greedoid partition problem
We show that the maximum matroid–greedoid partition problem is NP-hard to approximate to within 1 / 2 + ε for any ε > 0 , which matches the trivial factor 1/2 approximation algorithm. The main tool in our hardness of approximation result is an extractor code with polynomial rate, alphabet size an...
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| Published in: | Theoretical computer science Vol. 410; no. 8; pp. 859 - 866 |
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| Main Authors: | , |
| Format: | Journal Article |
| Language: | English |
| Published: |
Oxford
Elsevier B.V
01.03.2009
Elsevier |
| Subjects: | |
| ISSN: | 0304-3975, 1879-2294 |
| Online Access: | Get full text |
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| Summary: | We show that the maximum matroid–greedoid partition problem is NP-hard to approximate to within
1
/
2
+
ε
for any
ε
>
0
, which matches the trivial factor 1/2 approximation algorithm. The main tool in our hardness of approximation result is an
extractor code with polynomial rate, alphabet size and list size, together with an efficient algorithm for list-decoding. We show that the recent extractor construction of Guruswami, Umans and Vadhan [V. Guruswami, C. Umans, S.P. Vadhan, Unbalanced expanders and randomness extractors from Parvaresh-Vardy codes, in: IEEE Conference on Computational Complexity, IEEE Computer Society, 2007, pp. 96–108] can be used to obtain a code with these properties.
We also show that the parameterized matroid–greedoid partition problem is fixed-parameter tractable. |
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| ISSN: | 0304-3975 1879-2294 |
| DOI: | 10.1016/j.tcs.2008.11.019 |