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Perfect Constraints Are Tractable [chapter]

András Z. Salamon, Peter G. Jeavons
Lecture Notes in Computer Science  
In each of these cases we show that the associated microstructure of the problem is a perfect graph, and hence they are all part of the same larger family of tractable problems.  ...  By using recent results from graph theory, including the Strong Perfect Graph Theorem, we obtain a unifying framework for a number of tractable classes of constraint problems.  ...  All chordal and co-chordal graphs are perfect [6] . Jégou noted that binary constraint problems with chordal MS form a tractable class [7] .  ... 
doi:10.1007/978-3-540-85958-1_35 fatcat:7ri5vke2gfcgvpeptnm5euku7a

A New Hybrid Tractable Class of Soft Constraint Problems [chapter]

Martin C. Cooper, Stanislav Živný
2010 Lecture Notes in Computer Science  
In this paper we study hybrid tractability of soft constraint problems; that is, properties which guarantee tractability of the given soft constraint problem, but properties which do not depend only on  ...  We then introduce the joint-winner property, which allows us to define a novel hybrid tractable class of soft constraint problems with soft binary and unary constraints.  ...  The tractability of VCSPs with perfect microstructure (complement) and soft unary constraints was also pointed out by Takhanov [32] .  ... 
doi:10.1007/978-3-642-15396-9_15 fatcat:uz2h3ndrw5dcra2phvo5xzfqna

On the efficiency of checking perfect privacy

Ashwin Machanavajjhala, Johannes Gehrke
2006 Proceedings of the twenty-fifth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems - PODS '06  
In this paper, we show that for large interesting subclasses of conjunctive queries enforcing perfect privacy is tractable.  ...  However, if QS and QV are arbitrary conjunctive queries, the problem of checking whether QV discloses any information about QS is known to be Π p 2 -complete.  ...  Any opinions, findings, conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the sponsors.  ... 
doi:10.1145/1142351.1142375 dblp:conf/pods/MachanavajjhalaG06 fatcat:fbr6hv5cufcnlc222vgoxk4wjq

Page 1326 of Mathematical Reviews Vol. , Issue 98B [page]

1998 Mathematical Reviews  
We also show that there arises a range of constraints defined by two threshold values in which the firms’ outputs are below the constraint level in the steady state.  ...  Since combinatorial games are completely determined, the question at hand is the efficiency and tractability of the strategies.  ... 

Tractability in constraint satisfaction problems: a survey

Clément Carbonnel, Martin C. Cooper
2015 Constraints  
Acknowledgments We are grateful to Peter Jeavons and StanislavŽivný for their detailed comments on a first draft of this paper, and to the reviewers for their constructive comments.  ...  Since a maximum clique in a perfect graph can be found in polynomial time [99] , the class of binary CSP instances with a perfect microstructure is tractable [149] .  ...  Interesting examples of binary CSP instances whose microstructure is perfect are instances with arbitrary domains and a constraint X i = X j between each pair of variables (or, alternatively, unary constraints  ... 
doi:10.1007/s10601-015-9198-6 fatcat:fl7kxmceh5bqzpyd2c37rtohii

Consistency of Chordal RCC-8 Networks

M. Sioutis, M. Koubarakis
2012 2012 IEEE 24th International Conference on Tools with Artificial Intelligence  
Given an RCC-8 network with only tractable RCC-8 relations, we show that it can be solved very efficiently with PyRCC8 by making its underlying constraint graph chordal and running path consistency on  ...  We prove this by using the fact that RCC-8 networks with relations from the maximal tractable subsetsĤ8, C8, and Q8 of RCC-8 have the patchwork property.  ...  We assume that the reader is familiar with the following concepts that are not defined explicitly in this paper due to space constraints: constraint networks and their corresponding constraint graphs,  ... 
doi:10.1109/ictai.2012.66 dblp:conf/ictai/SioutisK12 fatcat:v2sc2hkjenfu3dfwr2x7qgykxe

Efficient Solutions for Weighted Sum Rate Maximization in Multicellular Networks With Channel Uncertainties

Muhammad Fainan Hanif, Le-Nam Tran, Antti Tolli, Markku Juntti, Savo Glisic
2013 IEEE Transactions on Signal Processing  
With perfect channel information available at the base stations, we first present a novel fast converging algorithm that solves the WSRM problem.  ...  The results clearly indicate the performance gain compared to the case when channel uncertainties are ignored in the design process.  ...  We observe that in addition to being nonconvex, it also suffers from tractability issues. In particular, a part from the power constraints, all remaining constraints are semi-infinite in nature.  ... 
doi:10.1109/tsp.2013.2278815 fatcat:pwzfskxvkjbdrlm2rzqqx3dxw4

Transformations of representation in constraint satisfaction

András Z. Salamon
2015 Constraints  
In this thesis I study constraint satisfaction problems or CSPs. These require determining whether values can be assigned to variables so that all constraints are satisfied.  ...  For the common case where all constraints involve only two variables, I show how the microstructure can be used to define CSPs that are tractable because their clause structures fall within classes of  ...  Both of these classes are perfect, and can be combined to obtain a larger tractable class.  ... 
doi:10.1007/s10601-015-9224-8 fatcat:lollakqzx5h7xeajtfrmaz6u4q

A Dichotomy Theorem for the General Minimum Cost Homomorphism Problem

Rustem Takhanov, Marc Herbstritt
2010 Symposium on Theoretical Aspects of Computer Science  
In the constraint satisfaction problem (CSP ), the aim is to find an assignment of values to a set of variables subject to specified constraints.  ...  Let M inHom (Γ) denote the M inHom problem parameterized by the set of predicates allowed for constraints.  ...  The NP-hardness results are collected in Section 4 followed by the building blocks for the tractability result: existence of majority polymorphisms (Section 5) and connections with optimization in perfect  ... 
doi:10.4230/lipics.stacs.2010.2493 dblp:conf/stacs/Takhanov10 fatcat:bz3i6ogsrvbpdfkt2goxp6k7um

A Dichotomy Theorem for General Minimum Cost Homomorphism Problem [article]

Rustem Takhanov
2010 arXiv   pre-print
In the constraint satisfaction problem (CSP), the aim is to find an assignment of values to a set of variables subject to specified constraints.  ...  Let MinHom(Γ) denote the MinHom problem parameterized by the set of predicates allowed for constraints.  ...  A constraint language Γ over A is called a maximal tractable constraint language if it is tractable and is not contained in any other tractable languages.  ... 
arXiv:0708.3226v7 fatcat:vh7cncsje5ccvm23kfb2d2g7lm

Hybrid tractability of valued constraint problems

Martin C. Cooper, Stanislav Živný
2011 Artificial Intelligence  
Soft constraint problems are a generalisation of the CSP which allow the user to model optimisation problems.  ...  In this work, we initiate the study of hybrid tractability of soft constraint problems; that is, properties which guarantee tractability of the given soft constraint problem, but which do not depend only  ...  The tractability of VCSPs with perfect micro-structure and soft unary constraints was also independently pointed out by Takhanov [21] and Jebara [27] .  ... 
doi:10.1016/j.artint.2011.02.003 fatcat:otqplqno5fah3if7z2f4gc2zaq

Intractability and the use of heuristics in psychological explanations

Iris van Rooij, Cory D. Wright, Todd Wareham
2010 Synthese  
We argue that such explanations are actually dysfunctional, and rebut five possible objections. We then propose computational-level theory revision as a principled and workable alternative.  ...  of perfection or optimization are not sufficient for rendering computational-level theories tractable.  ...  It is known from computational complexity theory, however, that perfection or optimization are neither necessary nor sufficient conditions for intractability (cf.  ... 
doi:10.1007/s11229-010-9847-7 fatcat:qkekuzyk6bfkpbod5hlztbpkfe

Forthcoming papers

1995 Artificial Intelligence  
The key steps in this development approach are task analysis, method selection (from a library), and method configuration.  ...  Cooper, Tractable constraints on ordered domains Finding solutions to a constraint satisfaction problem is known to be an NP-complete problem in general, but may be tractable in cases where either the  ...  In particular, we show that in a precise sense agents in the structures considered by Levesque and Lakemeyer are perfect reasoners in NPL. PG. Jeavons, M.C.  ... 
doi:10.1016/0004-3702(95)90032-2 fatcat:qlx2isnt6jfelkekesv6affv7a

The Tractability of CSP Classes Defined by Forbidden Patterns

D. A. Cohen, M. C. Cooper, P. Creed, D. Marx, A. Z. Salamon
2012 The Journal of Artificial Intelligence Research  
Although we are not close to obtaining a complete characterisation concerning the tractability of general forbidden patterns, we prove a dichotomy in a special case: classes of problems that arise when  ...  We show that this framework generalises certain known hybrid tractable classes.  ...  First it was observed that the class of instances with a perfect microstructure is tractable (Salamon & Jeavons, 2008) .  ... 
doi:10.1613/jair.3651 fatcat:6tfaqcsoeffu7oxfwrkj426wz4

Fixed-Parameter Tractability of almost CSP Problem with Decisive Relations [chapter]

Chihao Zhang, Hongyang Zhang
2012 Lecture Notes in Computer Science  
Both cases are shown to be fixed-parameter tractable (FPT).  ...  Two special cases have been studied: when the constraints are inequality relations (Guo et al., WADS 2005) and when the constraints are OR type relations (Razgon and O'Sullivan, ICALP 2008).  ...  We are grateful to anonymous referees for pointing out some mistakes and their suggestion for presentation.  ... 
doi:10.1007/978-3-642-29700-7_21 fatcat:l6bximhtkjat7bgris5thihzgm
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