eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2006-11-15
6401
1
14
10.4230/DagSemProc.06401.1
article
06401 Abstracts Collection – Complexity of Constraints
Creignou, Nadia
Kolaitis, Phokion
Vollmer, Heribert
From 01.10.06 to 06.10.06, the Dagstuhl Seminar 06401 ``Complexity of Constraints'' was held in the International Conference and Research Center (IBFI),
Schloss Dagstuhl.
During the seminar, several participants presented their current
research, and ongoing work and open problems were discussed. Abstracts of
the presentations given during the seminar as well as abstracts of
seminar results and ideas are put together in this paper. The first section
describes the seminar topics and goals in general.
Links to extended abstracts or full papers are provided, if available.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol06401/DagSemProc.06401.1/DagSemProc.06401.1.pdf
Constraint satisfaction problems
computational complexity
universal algebra
mathematical logic
finite model theory
eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2006-11-15
6401
1
6
10.4230/DagSemProc.06401.2
article
06401 Executive Summary – Complexity of Constraints
Creignou, Nadia
Kolaitis, Phokion
Vollmer, Heribert
In this document we describe the original motivation and goals of the seminar as well as the sequence of talks given during the seminar.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol06401/DagSemProc.06401.2/DagSemProc.06401.2.pdf
Constraint satisfaction problems
complexity
eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2006-11-15
6401
1
22
10.4230/DagSemProc.06401.3
article
A Unifying Theory of Structural Decompostions for the Constraint Satisfaction Problems
Cohen, David
Gyssens, Marc
Jeavons, Peter
In this talk (draft paper) we develop the theory of structural decompositions for the CSP. We begin with the very general notion of a guarded decomposition and make several simplifying assumptions to arrive a the definition of an acyclic guarded cover.
We show how many existing decompositions can seen as acyclic guarded covers. We develop a generic algorithm for discovering acyclic guarded covers under the further assumption that they have a join tree satisfying a simple extra condition. We show that many existing decompositions do in fact satisfy this extra condition.
Using this theory we are able to describe a new class of structural decompostion which we call spread cuts. These generalise many existing decomposition methods. We present a class of hypergraphs whose spread cut width is significantly smaller than their hypertree width.
The definition of a guarded decomposition and the algorithm for discovering them were motvated by the similar algorithms developed by Gottlob, Scarcello and Leone in their work on hypertrees. The authors also wish to acknowledge that an acyclic guarded decomposition is very similar to a generalised hypertree decomposition as described in the hypertree literature.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol06401/DagSemProc.06401.3/DagSemProc.06401.3.pdf
Structural decomposition
spread cut
eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2006-11-15
6401
1
0
10.4230/DagSemProc.06401.4
article
Constraint satisfaction problems in clausal form: Autarkies, minimal unsatisfiability, and applications to hypergraph inequalities
Kullmann, Oliver
Generalised CNFs are considered using such literals, which exclude exactly one possible value from the domain of the variable. First we consider poly-time SAT decision (and fixed-parameter tractability) exploiting matching theory. Then we consider
irredundant generalised CNFs, and characterise some extremal minimally
unsatisfiable CNFs.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol06401/DagSemProc.06401.4/DagSemProc.06401.4.pdf
Signed CNF
autarkies
minimal unsatisfiable
hypergraph colouring
block designs
eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2006-11-15
6401
1
15
10.4230/DagSemProc.06401.5
article
Constraint Satisfaction with Succinctly Specified Relations
Chen, Hubie
Grohe, Martin
The general intractability of the constraint satisfaction problem
has motivated the study of the complexity of restricted cases of this problem.
Thus far, the literature has primarily considered the formulation
of the CSP where constraint relations are given explicitly.
We initiate the systematic study of CSP complexity with
succinctly specified constraint relations.
This is joint work with Hubie Chen.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol06401/DagSemProc.06401.5/DagSemProc.06401.5.pdf
Constraint satisfaction
complexity
succinct representations
eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2006-11-15
6401
1
25
10.4230/DagSemProc.06401.6
article
Enumerating all Solutions for Constraint Satisfaction Problems
Schnoor, Henning
Schnoor, Ilka
We contribute to the study of efficient enumeration algorithms for all solutions of constraint satisfaction problems. The only algorithm known so far, presented by Creignou and HÃƒÂ©brard and generalized by Cohen, reduces the enumeration problem for a constraint language $Gamma$ to the decision problem for a slightly enlarged constraint language $Gamma^+,$ i.e., it yields an efficient enumeration algorithm for the case where $mathrm{CSP}(Gamma^+)$ is tractable. We develop a new class of algorithms, yielding efficient enumeration algorithms for a broad class of constraint languages. For the three-element domain, we achieve a first step towards a dichotomy theorem for the enumeration problem.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol06401/DagSemProc.06401.6/DagSemProc.06401.6.pdf
Complexity
constraint satisfaction
enumeration
eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Dagstuhl Seminar Proceedings
1862-4405
2006-11-15
6401
1
18
10.4230/DagSemProc.06401.7
article
New Algebraic Tools for Constraint Satisfaction
Schnoor, Henning
Schnoor, Ilka
The Galois correspondence involving polymorphisms and co-clones
has received a lot of attention in regard to constraint satisfaction problems.
However, it fails if we are interested in a reduction giving equivalence
instead of only satisfiability-equivalence. We show how a similar
Galois connection involving weaker closure operators can be applied for
these problems. As an example of the usefulness of our construction, we
show how to obtain very short proofs of complexity classifications in this
context.
https://drops.dagstuhl.de/storage/16dagstuhl-seminar-proceedings/dsp-vol06401/DagSemProc.06401.7/DagSemProc.06401.7.pdf
Constraints
Partial Clones
Galois Correspondence