arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1909.00530math.COcs.DS
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燃烧两个世界:燃烧稠密和树状图的算法

Burning Two Worlds: Algorithms for Burning Dense and Tree-like Graphs

Shahin Kamali, Avery Miller, Kenny Zhang

摘要:

图燃烧是一种在网络中传播社会影响力的简单模型。目标是测量火灾(例如,一条假新闻)可以在网络中传播。燃烧过程是在不连续的几轮中进行的。在每一轮中,一个新的火在一个选定的顶点爆发并燃烧它。同时,旧的火延伸到它们的邻居并燃烧它们。燃烧计划选择在每一轮中新的火灾发生的地方,燃烧问题要求在最小轮数中燃烧所有顶点的计划,称为图的燃烧数。燃烧问题是已知的NP-难,即使图是一棵树或一个不相交的路径集。对于连通图,已证实燃烧最多需要$\lceil \sqrt{n} \rceil$轮。本文从两个方面对图燃烧算法进行了研究。首先,我们考虑具有最小度$δ$的图。我们提出了一个算法,烧伤任何图的大小$n$在最多$\sqrt{\frac{24n}{δ+1}}$轮。特别地,对于具有$δ\in Θ(n)$的稠密图,所有顶点在恒定轮数中被烧毁。更有趣的是,即使当$δ$是一个常数,是独立的图形大小,我们的算法回答了燃烧的图形猜想肯定的燃烧在最多$\lceil \sqrt{n} \rceil$轮。接下来,我们考虑具有有界路径长度或树长度的燃烧图。这些包括许多图族,包括连通区间图和连通弦图。我们证明了任何具有路径长度$pl$和直径$d$的图都可以在$\lceil \sqrt{d-1} \rceil + pl$轮中燃烧。我们的算法确保了有界路径长度的图的近似比为$1+o(1)$。我们介绍另一种算法,实现了近似比$2+o(1)$燃烧图的有界树长度。

英文摘要:

Graph burning is a simple model for the spread of social influence in networks. The objective is to measure how quickly a fire (e.g., a piece of fake news) can be spread in a network. The burning process takes place in discrete rounds. In each round, a new fire breaks out at a selected vertex and burns it. Meanwhile, the old fires extend to their neighbours and burn them. A burning schedule selects where the new fire breaks out in each round, and the burning problem asks for a schedule that burns all vertices in a minimum number of rounds, termed the burning number of the graph. The burning problem is known to be NP-hard even when the graph is a tree or a disjoint set of paths. For connected graphs, it has been conjectured that burning takes at most $\lceil \sqrt{n} \rceil$ rounds. We approach the algorithmic study of graph burning from two directions. First, we consider graphs with minimum degree $δ$. We present an algorithm that burns any graph of size $n$ in at most $\sqrt{\frac{24n}{δ+1}}$ rounds. In particular, for dense graphs with $δ\in Θ(n)$, all vertices are burned in a constant number of rounds. More interestingly, even when $δ$ is a constant that is independent of the graph size, our algorithm answers the graph-burning conjecture in the affirmative by burning the graph in at most $\lceil \sqrt{n} \rceil$ rounds. Next, we consider burning graphs with bounded path-length or tree-length. These include many graph families including connected interval graphs and connected chordal graphs. We show that any graph with path-length $pl$ and diameter $d$ can be burned in $\lceil \sqrt{d-1} \rceil + pl$ rounds. Our algorithm ensures an approximation ratio of $1+o(1)$ for graphs of bounded path-length. We introduce another algorithm that achieves an approximation ratio of $2+o(1)$ for burning graphs of bounded tree-length.

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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