License: Creative Commons Attribution 3.0 Unported license (CC BY 3.0)
When quoting this document, please refer to the following
DOI: 10.4230/LIPIcs.STACS.2016.22
URN: urn:nbn:de:0030-drops-57236
URL: http://dagstuhl.sunsite.rwth-aachen.de/volltexte/2016/5723/
Bonnet, Édouard ;
Lampis, Michael ;
Paschos, Vangelis Th.
Time-Approximation Trade-offs for Inapproximable Problems
Abstract
In this paper we focus on problems which do not admit a constant-factor approximation in polynomial time and explore how quickly their approximability improves as the allowed running time is gradually increased from polynomial to (sub-)exponential.
We tackle a number of problems: For MIN INDEPENDENT DOMINATING SET, MAX INDUCED PATH, FOREST and TREE, for any r(n), a simple, known scheme gives an approximation ratio of r in time roughly r^{n/r}. We show that, for most values of r, if this running time could be significantly improved the ETH would fail. For MAX MINIMAL VERTEX COVER we give a non-trivial sqrt{r}-approximation in time 2^{n/{r}}. We match this with a similarly tight result. We also give a log(r)-approximation for MIN ATSP in time 2^{n/r} and an r-approximation for MAX GRUNDY COLORING in time r^{n/r}.
Furthermore, we show that MIN SET COVER exhibits a curious behavior in this super-polynomial setting: for any delta>0 it admits an m^delta-approximation, where m is the number of sets, in just quasi-polynomial time. We observe that if such ratios could be achieved in polynomial time, the ETH or the Projection Games Conjecture would fail.
BibTeX - Entry
@InProceedings{bonnet_et_al:LIPIcs:2016:5723,
author = {{\'E}douard Bonnet and Michael Lampis and Vangelis Th. Paschos},
title = {{Time-Approximation Trade-offs for Inapproximable Problems}},
booktitle = {33rd Symposium on Theoretical Aspects of Computer Science (STACS 2016)},
pages = {22:1--22:14},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-001-9},
ISSN = {1868-8969},
year = {2016},
volume = {47},
editor = {Nicolas Ollinger and Heribert Vollmer},
publisher = {Schloss Dagstuhl--Leibniz-Zentrum fuer Informatik},
address = {Dagstuhl, Germany},
URL = {http://drops.dagstuhl.de/opus/volltexte/2016/5723},
URN = {urn:nbn:de:0030-drops-57236},
doi = {10.4230/LIPIcs.STACS.2016.22},
annote = {Keywords: Algorithm, Complexity, Polynomial and Subexponential Approximation, Reduction, Inapproximability}
}
Keywords: |
|
Algorithm, Complexity, Polynomial and Subexponential Approximation, Reduction, Inapproximability |
Collection: |
|
33rd Symposium on Theoretical Aspects of Computer Science (STACS 2016) |
Issue Date: |
|
2016 |
Date of publication: |
|
16.02.2016 |