The complexity of approximating conservative counting CSPs
The complexity of approximating conservative counting CSPs
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DOI:
10.1016/j.jcss.2014.06.006
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发表时间:
2012-08
期刊:
影响因子:
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通讯作者:
X. Chen;M. Dyer;L. A. Goldberg;M. Jerrum;P. Lu;Colin McQuillan;David Richerby
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文献类型:
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作者:
X. Chen;M. Dyer;L. A. Goldberg;M. Jerrum;P. Lu;Colin McQuillan;David Richerby
We study the complexity of the approximate weighted counting constraint satisfaction problem# CSP (F). In the conservative case, where F contains all unary functions, a classification is known over the Boolean domain; we extend this to arbitrary finite domains. We show that if F is “weakly log-modular”, then# CSP (F) is in FP. Otherwise, it is at least as difficult to approximate as# BIS (counting independent sets in bipartite graphs).# BIS is complete for the complexity class# R H Π 1, and believed to be intractable. We further sub-divide the# BIS-hard case: if F is “weakly log-supermodular”,# CSP (F) is as easy as a Boolean log-supermodular weighted# CSP; otherwise, we show that it is NP-hard to approximate. Finally, we give a full trichotomy for the arity-2 case:# CSP (F) is in FP, is# BIS-equivalent, or is equivalent to# SAT (approximately counting the satisfying assignments of Boolean CNF formulas). We also discuss algorithmic aspects of our classification.