arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2008.09822cs.DScs.DM
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树深分解中最小分离子的大小

On the Size of Minimal Separators for Treedepth Decomposition

Zijian Xu, Vorapong Suppakitpaisarn

摘要:

树深度分解有几个实际应用,可以用来加速许多参数化算法。有几项工作旨在设计一个可扩展的算法来计算精确的树深度分解。这些作品包括基于一组所有最小分隔符的作品。在这些算法中,虽然枚举了许多最小分隔符,但用于最优解的最小分隔符根据经验非常小。因此,分析最小分隔符大小的上界是一个重要的问题,因为它有可能显着减少计算时间。如果$td(G) = |S| + td(G \backslash S)$,则最小分隔符$S$称为最优顶部分隔符,其中$td(G)$表示$G$的树深度。然后,我们有两个理论结果的最佳顶部分离器的大小。(1)对于任何$G$,存在最佳顶部分隔符$S$,使得$|S| \le 2tw(G)$,其中$tw(G)$是$G$的树宽。(2)对于任何$c < 2$,存在图$G$,使得$G$的任何最优顶部分隔符$S$具有$|S| > c \cdot tw(G)$,即,第一个结果给出了最佳顶部分隔器的尺寸的严格界限。

英文摘要:

Treedepth decomposition has several practical applications and can be used to speed up many parameterized algorithms. There are several works aiming to design a scalable algorithm to compute exact treedepth decompositions. Those include works based on a set of all minimal separators. In those algorithms, although a number of minimal separators are enumerated, the minimal separators that are used for an optimal solution are empirically very small. Therefore, analyzing the upper bound on the size of minimal separators is an important problem because it has the potential to significantly reduce the computation time. A minimal separator $S$ is called an optimal top separator if $td(G) = |S| + td(G \backslash S)$, where $td(G)$ denotes the treedepth of $G$. Then, we have two theoretical results on the size of optimal top separators. (1) For any $G$, there is an optimal top separator $S$ such that $|S| \le 2tw(G)$, where $tw(G)$ is the treewidth of $G$. (2) For any $c < 2$, there exists a graph $G$ such that any optimal top separator $S$ of $G$ have $|S| > c \cdot tw(G)$, i.e., the first result gives a tight bound on the size of an optimal top separator.

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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