The complexity of temporal constraint satisfaction problems
STOC '08 Proceedings of the fortieth annual ACM symposium on Theory of computing
Maximal infinite-valued constraint languages
Theoretical Computer Science
The complexity of temporal constraint satisfaction problems
Journal of the ACM (JACM)
Proceedings of the forty-third annual ACM symposium on Theory of computing
Quantified Equality Constraints
SIAM Journal on Computing
An Algebraic Preservation Theorem for Aleph-Zero Categorical Quantified Constraint Satisfaction
LICS '12 Proceedings of the 2012 27th Annual IEEE/ACM Symposium on Logic in Computer Science
Journal of Artificial Intelligence Research
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We classify the computational complexity of all constraint satisfaction problems where the constraint language is preserved by all permutations of the domain. A constraint language is preserved by all permutations of the domain if and only if all the relations in the language can be defined by boolean combinations of the equality relation. We call the corresponding constraint languages equality constraint languages. For the classification result we apply the universal-algebraic approach to infinite-valued constraint satisfaction, and show that an equality constraint language is tractable if it admits a constant unary polymorphism or an injective binary polymorphism, and is NP-complete otherwise. We also discuss how to determine algorithmically whether a given constraint language is tractable.