Easy Problems are Sometimes Hard (1994)
| Venue: | Artificial Intelligence |
| Citations: | 75 - 17 self |
BibTeX
@ARTICLE{Gent94easyproblems,
author = {Ian Gent and Toby Walsh},
title = {Easy Problems are Sometimes Hard},
journal = {Artificial Intelligence},
year = {1994},
volume = {70},
pages = {335--345}
}
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Abstract
We present a detailed experimental investigation of the easy-hard-easy phase transition for randomly generated instances of satisfiability problems. Problems in the hard part of the phase transition have been extensively used for benchmarking satisfiability algorithms. This study demonstrates that problem classes and regions of the phase transition previously thought to be easy can sometimes be orders of magnitude more difficult than the worst problems in problem classes and regions of the phase transition considered hard. These difficult problems are either hard unsatisfiable problems or are satisfiable problems which give a hard unsatisfiable subproblem following a wrong split. Whilst these hard unsatisfiable problems may have short proofs, these appear to be difficult to find, and other proofs are long and hard. This paper is a revised version of Research Paper 642, available from the department of Artificial Intelligence, Edinburgh. This version is to appear in the journal Artific...
Citations
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| 44 | Evidence for satisfiability threshold for random 3CNF formulas - Larrabee, T, et al. - 1993 |
| 26 | The pure literal rule and polynomial average time - Purdom, Brown |
| 4 | Easy Problems are Sometimes Hard. Research Paper 642 - Gent, Walsh - 1993 |
| 3 | The SAT phase transition. Research Paper 679 - Gent, Walsh - 1994 |
| 1 | The Hardest Random - Gent, Walsh - 1994 |
