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arXiv 1810.04620cs.DScs.CC
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无H图中独立集的参数化复杂度

Parameterized Complexity of Independent Set in H-Free Graphs

Édouard Bonnet, Nicolas Bousquet, Pierre Charbit, Stéphan Thomassé, Rémi Watrigant

摘要:

本文研究了无$H$图类中的最大独立集(MIS)的复杂性.鉴于问题仍然$NP$ -硬大多数图$H$,我们研究了其固定参数的易处理性和$FPT$和$W[1]$ -硬的情况下,对两分法的进展。我们首先表明,MIS仍然$W[1]$ -硬禁止同时$K_{1, 4}$,任何有限集的周期长度至少$4$,和任何有限集的树至少有两个分支顶点的图。特别地,这回答了Dabrowski等人关于无$C_4$图的一个公开问题。然后,我们扩展的多项式算法Alekseev当$H$是一个不相交的边的联合$FPT$算法时,$H$是一个不相交的联合团。我们还提供了一个框架来解决其他几种情况下,这是一个概括的概念,伴随着提取一个特定的结构,使用拉姆齐定理的\emph{iterative expansion}。迭代扩展是所谓的\emph{iterative compression}的最大化版本。我们相信,我们的框架可以解决其他类似的图形问题的独立利益。最后,我们提出了积极和消极的结果存在的多项式(图灵)核的几个图$H$。

英文摘要:

In this paper, we investigate the complexity of Maximum Independent Set (MIS) in the class of $H$-free graphs, that is, graphs excluding a fixed graph as an induced subgraph. Given that the problem remains $NP$-hard for most graphs $H$, we study its fixed-parameter tractability and make progress towards a dichotomy between $FPT$ and $W[1]$-hard cases. We first show that MIS remains $W[1]$-hard in graphs forbidding simultaneously $K_{1, 4}$, any finite set of cycles of length at least $4$, and any finite set of trees with at least two branching vertices. In particular, this answers an open question of Dabrowski et al. concerning $C_4$-free graphs. Then we extend the polynomial algorithm of Alekseev when $H$ is a disjoint union of edges to an $FPT$ algorithm when $H$ is a disjoint union of cliques. We also provide a framework for solving several other cases, which is a generalization of the concept of \emph{iterative expansion} accompanied by the extraction of a particular structure using Ramsey's theorem. Iterative expansion is a maximization version of the so-called \emph{iterative compression}. We believe that our framework can be of independent interest for solving other similar graph problems. Finally, we present positive and negative results on the existence of polynomial (Turing) kernels for several graphs $H$.

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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