arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2107.05928cs.LO
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具有连通算子的一阶逻辑

First-Order Logic with Connectivity Operators

Nicole Schirrmacher, Sebastian Siebertz, Alexandre Vigny

摘要:

一阶逻辑(FO)可以在图上表达许多算法问题,例如独立集和支配集问题,并通过解大小进行参数化。另一方面,FO不能表达两个顶点是否连通的非常简单的算法问题。我们丰富FO与连接谓词,是专门用来表达算法图的属性,通常在参数化算法研究。通过添加原子谓词$conn_k (x, y, z_1 ,\ldots, z_k)$,如果在$z_1,\ldots,z_k$的(赋值)被删除后,$x$(的赋值)和$y$之间存在路径,则在图中保持为真,我们获得分隔符逻辑$FO + conn$。我们表明,分离器逻辑可以表示许多有趣的问题,如反馈顶点集问题和消除距离问题的一阶可定义类。然后,我们研究了分离器逻辑的局限性,并证明它不能表示平面性,特别是,不相交的路径问题。我们通过添加原子谓词$disjoint-paths_k [(x_1, y_1 ),\ldots , (x_k , y_k )]$来获得更强的不相交路径逻辑$FO + DP$,如果对于所有$1 \le i \le k$,$x_i$和$y_i$(的赋值)之间存在内部顶点不相交路径,则这些原子谓词的求值为真。不相交路径逻辑可以表示不相交路径问题、(拓扑)子包含问题、命中(拓扑)子问题等等。最后,我们比较了新逻辑与传递闭包逻辑和一元二阶逻辑的表达能力。

英文摘要:

First-order logic (FO) can express many algorithmic problems on graphs, such as the independent set and dominating set problem, parameterized by solution size. On the other hand, FO cannot express the very simple algorithmic question of whether two vertices are connected. We enrich FO with connectivity predicates that are tailored to express algorithmic graph properties that are commonly studied in parameterized algorithmics. By adding the atomic predicates $conn_k (x, y, z_1 ,\ldots, z_k)$ that hold true in a graph if there exists a path between (the valuations of) $x$ and $y$ after (the valuations of) $z_1,\ldots,z_k$ have been deleted, we obtain separator logic $FO + conn$. We show that separator logic can express many interesting problems such as the feedback vertex set problem and elimination distance problems to first-order definable classes. We then study the limitations of separator logic and prove that it cannot express planarity, and, in particular, not the disjoint paths problem. We obtain the stronger disjoint-paths logic $FO + DP$ by adding the atomic predicates $disjoint-paths_k [(x_1, y_1 ),\ldots , (x_k , y_k )]$ that evaluate to true if there are internally vertex disjoint paths between (the valuations of) $x_i$ and $y_i$ for all $1 \le i \le k$. Disjoint-paths logic can express the disjoint paths problem, the problem of (topological) minor containment, the problem of hitting (topological) minors, and many more. Finally, we compare the expressive power of the new logics with that of transitive closure logics and monadic second-order logic.

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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