一句话:证明带任意多等价关系的一元否定片段具有有限模型性质,并确定其可满足性为 2-ExpTime 完全。
本文研究一阶逻辑一元否定片段(UNF)的扩展:允许任意多个二元符号被解释为等价关系。作者证明该扩展具有有限模型性质,并给出小模型上界:每个可满足公式都有一个规模至多双指数的模型。据此,他们确定该逻辑的可满足性问题(等价于有限可满足性)是 2-ExpTime 完全的。论文还将这些结果迁移到一个带等价关系的受限 guarded negation fragment 变体。
We consider an extension of the unary negation fragment of first-order logic in which arbitrarily many binary symbols may be required to be interpreted as equivalence relations. We show that this extension has the finite model property. More specifically, we show that every satisfiable formula has a model of at most doubly exponential size. We argue that the satisfiability (= finite satisfiability) problem for this logic is 2-ExpTime-complete. We also transfer our results to a restricted variant of the guarded negation fragment with equivalence relations.