论文标题

有效地近似于无尺度网络上的顶点覆盖物,具有潜在双曲线几何形状

Efficiently Approximating Vertex Cover on Scale-Free Networks with Underlying Hyperbolic Geometry

论文作者

Bläsius, Thomas, Friedrich, Tobias, Katzmann, Maximilian

论文摘要

在网络中找到最小顶点覆盖物是一个基本的NP完整图问题。处理其计算硬度的一种方法是将算法的定性性能(允许非最佳输出)交换,以改善运行时间。对于顶点覆盖问题,在理解这种权衡方面,理论与实践之间存在差距。一方面,众所周知,在$ \ sqrt {2} $的一倍之内,将最小顶点盖近似于NP-HARD。另一方面,一种简单的贪婪算法在实践中产生接近最佳近似值。 理解这种差异的一种有希望的方法是认识到理论最坏情况与现实世界网络之间的差异。遵循这个方向,我们通过提供有效地计算出双曲线随机图上几乎最佳顶点覆盖近似值的算法来缩小理论和实践之间的差距。一个网络模型,在程度分布,聚类和小世界属性方面与现实世界网络紧密相似。更确切地说,我们的算法计算$(1 + o(1))$ - 近似值,几乎肯定是渐进的,并且运行时间为$ \ Mathcal {o}(M \ log(n))$。 所提出的算法是对成功的贪婪方法的适应,并通过在贪婪不是最佳状态的图表的一部分上改进了一个程序。这使得可以引入一个可以用于调整近似性能和运行时间之间的权衡的参数。我们对现实世界网络的经验评估表明,这可以改善贪婪方法的近乎最佳结果。

Finding a minimum vertex cover in a network is a fundamental NP-complete graph problem. One way to deal with its computational hardness, is to trade the qualitative performance of an algorithm (allowing non-optimal outputs) for an improved running time. For the vertex cover problem, there is a gap between theory and practice when it comes to understanding this tradeoff. On the one hand, it is known that it is NP-hard to approximate a minimum vertex cover within a factor of $\sqrt{2}$. On the other hand, a simple greedy algorithm yields close to optimal approximations in practice. A promising approach towards understanding this discrepancy is to recognize the differences between theoretical worst-case instances and real-world networks. Following this direction, we close the gap between theory and practice by providing an algorithm that efficiently computes nearly optimal vertex cover approximations on hyperbolic random graphs; a network model that closely resembles real-world networks in terms of degree distribution, clustering, and the small-world property. More precisely, our algorithm computes a $(1 + o(1))$-approximation, asymptotically almost surely, and has a running time of $\mathcal{O}(m \log(n))$. The proposed algorithm is an adaptation of the successful greedy approach, enhanced with a procedure that improves on parts of the graph where greedy is not optimal. This makes it possible to introduce a parameter that can be used to tune the tradeoff between approximation performance and running time. Our empirical evaluation on real-world networks shows that this allows for improving over the near-optimal results of the greedy approach.

扫码加入交流群

加入微信交流群

微信交流群二维码

扫码加入学术交流群,获取更多资源