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arXiv 1003.0802cs.LOcs.CC
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不含等式的正一阶逻辑的复杂性

The complexity of positive first-order logic without equality

Florent Madelaine, Barnaby Martin

摘要:

本文研究了在固定的有限结构B上求一阶逻辑无正等同性语句的复杂性。这可以被看作是非均匀量化的约束满足问题QCSP(B)的自然推广。我们引入满射超自同态,并使用它们来证明一个伽罗瓦连接,其特征在于可定义的正等式自由FO。通过代数方法,我们得出一个完整的复杂性分类为我们的问题B范围的大小最多为3的结构。具体来说,每个问题要么是在对数空间中,要么是NP完全的,要么是共NP完全的,要么是P空间完全的。

英文摘要:

We study the complexity of evaluating positive equality-free sentences of first-order (FO) logic over a fixed, finite structure B. This may be seen as a natural generalisation of the non-uniform quantified constraint satisfaction problem QCSP(B). We introduce surjective hyper-endomorphisms and use them in proving a Galois connection that characterises definability in positive equality-free FO. Through an algebraic method, we derive a complete complexity classification for our problems as B ranges over structures of size at most three. Specifically, each problem is either in Logspace, is NP-complete, is co-NP-complete or is Pspace-complete.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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