We study the constraint satisfaction problem (CSP) parameterized by a constraint language Γ (CSP(Γ)) and how the choice of Γ affects its worst-case time complexity. Under the exponential-time hypothesis (ETH), we rule out the existence of subexponential algorithms for finite-domain NP-complete CSP(Γ) problems. This extends to certain infinite-domain CSPs and structurally restricted problems. For CSPs with finite domain D and where all unary relations are available, we identify a relation S_D such that the time complexity of the NP-complete problem CSP({S_D}) is a lower bound for all NP-complete CSPs of this kind. We also prove that the time complexity of CSP({S_D}) strictly decreases when |D| increases (unless the ETH is false) and provide stronger complexity results in the special case when |D| = 3.
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机译:我们研究由约束语言γ(CSP(γ))参数化的约束满足问题(CSP),以及如何选择γ的最坏情况时间复杂度。在指数 - 时的假设(ETH)下,我们排除了有限域NP完整CSP(γ)问题的子折叠算法的存在。这延伸到某些无限域CSP和结构上限制的问题。对于具有有限域D的CSP以及所有联合关系可用,我们识别一个关系S_D,使得NP完整问题CSP({S_D})的时间复杂度是所有NP完整的CSP的下限。我们还证明了CSP({S_D})的时间复杂性严格地减少| D |增加(除非Eth是假)并在特殊情况下提供更强的复杂性结果| D | D | = 3。
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