Exploiting bipartiteness to identify yet another tractable subclass of CSP
1999 (English)In: Proceedings of the 5th International Conference on Principles and Practice of Constraint Programming (CP), Springer, 1999, Vol. 1713, 118-128Conference paper (Refereed)
The class of constraint satisfaction problems (CSPs) over finite domains has been shown to be NP-complete, but many tractable subclasses have been identified in the literature. In this paper we are interested in restrictions on the types of constraint relations in CSP instances. By a result of Jeavons et al. we know that a key to the complexity of classes arising from such restrictions is the closure properties of the sets of relations. It has been shown that sets of relations that are closed under constant, majority, affine, or associative, commutative, and idempotent (ACI) functions yield tractable subclasses of CSP. However, it has been unknown whether other closure properties may generate tractable subclasses. In this paper we introduce a class of tractable (in fact, SL-complete) CSPs based on bipartite graphs. We show that there are members of this class that are not closed under constant, majority, affine, or ACI functions, and that it, therefore, is incomparable with previously identified classes.
Lecture Notes in Computer Science, ISSN 0302-9743 ; 1713
National CategoryEngineering and Technology
IdentifiersURN: urn:nbn:se:liu:diva-49636DOI: 10.1007/978-3-540-48085-3_9OAI: oai:DiVA.org:liu-49636DiVA: diva2:270532