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arXiv 2402.06407cs.DS
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快速排序风格的近似算法用于锦标赛中反馈顶点集的一般化问题

Quick-Sort Style Approximation Algorithms for Generalizations of Feedback Vertex Set in Tournaments

Sushmita Gupta, Sounak Modak, Saket Saurabh, Sanjay Seetharaman

AI总结:

本文提出因子$2α$和$2$的随机近似算法,分别解决一般有向图(独立数$α$)和锦标赛中的最小权重反馈顶点集及其子集变体问题。

摘要:

有向图中的反馈顶点集(FVS)是顶点的子集,删除该子集后使有向图变为无环图。换言之,它击中(即相交)有向图中的所有环。Lokshtanov等人[TALG '21]给出了一个因子为2的随机近似算法,用于在锦标赛中寻找最小权重FVS。我们通过提出一个因子为$2α$的随机近似算法来推广该结果,该算法用于在独立数为$α$的有向图中寻找最小权重FVS;锦标赛是独立数为$1$的有向图,因此是该类图的一种推广。利用相同的框架,我们提出了一个因子为$2$的随机近似算法,用于在锦标赛中寻找最小权重子集FVS:给定图之外的一个顶点子集$S$,找到一个顶点子集,使其击中所有包含至少一个$S$中顶点的环。注意,锦标赛中的FVS是锦标赛中子集FVS的一个特例,其中$S = V(T)$。

英文摘要:

A feedback vertex set (FVS) in a digraph is a subset of vertices whose removal makes the digraph acyclic. In other words, it hits all cycles in the digraph. Lokshtanov et al. [TALG '21] gave a factor 2 randomized approximation algorithm for finding a minimum weight FVS in tournaments. We generalize the result by presenting a factor $2α$ randomized approximation algorithm for finding a minimum weight FVS in digraphs of independence number $α$; a generalization of tournaments which are digraphs with independence number $1$. Using the same framework, we present a factor $2$ randomized approximation algorithm for finding a minimum weight Subset FVS in tournaments: given a vertex subset $S$ in addition to the graph, find a subset of vertices that hits all cycles containing at least one vertex in $S$. Note that FVS in tournaments is a special case of Subset FVS in tournaments in which $S = V(T)$.

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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