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Complexity of clausal constraints over chains.

Creignou, N. and Hermann, M. and Krokhin, A. and Salzer, G. (2008) 'Complexity of clausal constraints over chains.', Theory of computing systems., 42 (2). pp. 239-255.


We investigate the complexity of the satisfiability problem of constraints over finite totally ordered domains. In our context, a clausal constraint is a disjunction of inequalities of the form x≥d and x≤d. We classify the complexity of constraints based on clausal patterns. A pattern abstracts away from variables and contains only information about the domain elements and the type of inequalities occurring in a constraint. Every finite set of patterns gives rise to a (clausal) constraint satisfaction problem in which all constraints in instances must have an allowed pattern. We prove that every such problem is either polynomially decidable or NP-complete, and give a polynomial-time algorithm for recognizing the tractable cases. Some of these tractable cases are new and have not been previously identified in the literature.

Item Type:Article
Keywords:Constraint satisfaction problems, Complexity, Finite totally ordered domains, Inequalities, Clausal patterns, Dichotomy theorem.
Full text:Full text not available from this repository.
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Date accepted:No date available
Date deposited:No date available
Date of first online publication:February 2008
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