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arXiv 1005.0670cs.DS
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无权图稀疏化的线性时间算法

A Linear-time Algorithm for Sparsification of Unweighted Graphs

Ramesh Hariharan, Debmalya Panigrahi

摘要:

给定一个无向图$G$和一个误差参数$ε> 0$,{ \em图稀疏化}问题需要对$G$中的边进行采样,并给予采样边适当的权重,以获得具有以下性质的稀疏图$G_ε$:$G_ε$中每个割的权重在$G$中相应割的权重的$(1\pm ε)$的因子内。如果$G$是未加权的,则最近已经开发了用于构建具有期望中的$O(n\log n/ε^2)$边缘的$G_ε$的$O(m\log n)$ -时间算法,以及用于构建具有期望中的$O(n\log^2 n/ε^2)$边缘的$G_ε$的$O(m)$ -时间算法(Hariharan-Panigrahi,2010)。在本文中,我们改进了这些结果,给出了一个$O(m)$ -时间算法,用于构造$G_ε$与$O(n\log n/ε^2)$边的期望,无权图。我们的算法是最佳的时间复杂度,此外,没有有效的算法是已知的稀疏$G_ε$。我们的算法是蒙特卡洛,即它产生正确的输出具有高概率,因为所有有效的图稀疏化算法。

英文摘要:

Given an undirected graph $G$ and an error parameter $ε> 0$, the {\em graph sparsification} problem requires sampling edges in $G$ and giving the sampled edges appropriate weights to obtain a sparse graph $G_ε$ with the following property: the weight of every cut in $G_ε$ is within a factor of $(1\pm ε)$ of the weight of the corresponding cut in $G$. If $G$ is unweighted, an $O(m\log n)$-time algorithm for constructing $G_ε$ with $O(n\log n/ε^2)$ edges in expectation, and an $O(m)$-time algorithm for constructing $G_ε$ with $O(n\log^2 n/ε^2)$ edges in expectation have recently been developed (Hariharan-Panigrahi, 2010). In this paper, we improve these results by giving an $O(m)$-time algorithm for constructing $G_ε$ with $O(n\log n/ε^2)$ edges in expectation, for unweighted graphs. Our algorithm is optimal in terms of its time complexity; further, no efficient algorithm is known for constructing a sparser $G_ε$. Our algorithm is Monte-Carlo, i.e. it produces the correct output with high probability, as are all efficient graph sparsification algorithms.

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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