Where the really hard problems aren’t
نویسندگان
چکیده
منابع مشابه
Where the Really Hard Problems Are
It is well known that for many NP-complete problems, such as K-Sat, etc., typical cases are easy to solve; so that computationally hard cases must be rare (assuming P = NP). This paper shows that NP-complete problems can be summarized by at least one "order parameter", and that the hard problems occur at a cri t ical value of such a parameter. This cri t ical value separates two regions of char...
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Voting is a simple mechanism to aggregate the preferences of agents. Many voting rules have been shown to be NP-hard to manipulate. However, a number of recent theoretical results suggest that this complexity may only be in the worst-case since manipulation is often easy in practice. In this paper, we show that empirical studies are useful in improving our understanding of this issue. We demons...
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Voting is a simple mechanism to aggregate the preferences of agents. Many voting rules have been shown to be NP-hard to manipulate. However, a number of recent theoretical results have suggested that this complexity may only be in the worst-case and manipulation may be easy in practice. In this paper, we show that empirical studies are useful in improving our understanding of this issue. We dem...
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Constraint satisfaction problems exhibit a phase transition as a problem parameter is varied, from a region where most problems are easy and soluble to a region where most problems are easy but insoluble. In the intervening phase transition region, the median problem diiculty is greatest. However, in the easy and soluble region, occasional exceptionally hard problems (ehps) can be found, which ...
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One possible escape from the Gibbard-Satterthwaite theorem is computational complexity. For example, it is NP-hard to compute if the STV rule can be manipulated. However, there is increasing concern that such results may not reflect the difficulty of manipulation in practice. In this tutorial, I survey recent results in this area. The Gibbard Satterthwaite theorem proves that, under some simple...
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ژورنال
عنوان ژورنال: Operations Research Perspectives
سال: 2020
ISSN: 2214-7160
DOI: 10.1016/j.orp.2020.100160