License: Creative Commons Attribution 3.0 Unported license (CC BY 3.0)
When quoting this document, please refer to the following
DOI: 10.4230/LIPIcs.IPEC.2017.1
URN: urn:nbn:de:0030-drops-85446
URL: http://dagstuhl.sunsite.rwth-aachen.de/volltexte/2018/8544/
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Agrawal, Akanksha ; Saurabh, Saket ; Tale, Prafullkumar

On the Parameterized Complexity of Contraction to Generalization of Trees

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Abstract

For a family of graphs F, the F-Contraction problem takes as an input a graph G and an integer k, and the goal is to decide if there exists S \subseteq E(G) of size at most k such that G/S belongs to F. Here, G/S is the graph obtained from G by contracting all the edges in S. Heggernes et al.[Algorithmica (2014)] were the first to study edge contraction problems in the realm of Parameterized Complexity. They studied \cal F-Contraction when F is a simple family of graphs such as trees and paths. In this paper, we study the F-Contraction problem, where F generalizes the family of trees. In particular, we define this generalization in a "parameterized way". Let T_\ell be the family of graphs such that each graph in T_\ell can be made into a tree by deleting at most \ell edges. Thus, the problem we study is T_\ell-Contraction. We design an FPT algorithm for T_\ell-Contraction running in time O((\ncol)^{O(k + \ell)} * n^{O(1)}). Furthermore, we show that the problem does not admit a polynomial kernel when parameterized by k. Inspired by the negative result for the kernelization, we design a lossy kernel for T_\ell-Contraction of size O([k(k + 2\ell)] ^{(\lceil {\frac{\alpha}{\alpha-1}\rceil + 1)}}).

BibTeX - Entry

@InProceedings{agrawal_et_al:LIPIcs:2018:8544,
  author =	{Akanksha Agrawal and Saket Saurabh and Prafullkumar Tale},
  title =	{{On the Parameterized Complexity of Contraction to Generalization of Trees}},
  booktitle =	{12th International Symposium on Parameterized and Exact Computation (IPEC 2017)},
  pages =	{1:1--1:12},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-051-4},
  ISSN =	{1868-8969},
  year =	{2018},
  volume =	{89},
  editor =	{Daniel Lokshtanov and Naomi Nishimura},
  publisher =	{Schloss Dagstuhl--Leibniz-Zentrum fuer Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{http://drops.dagstuhl.de/opus/volltexte/2018/8544},
  URN =		{urn:nbn:de:0030-drops-85446},
  doi =		{10.4230/LIPIcs.IPEC.2017.1},
  annote =	{Keywords: Graph Contraction, Fixed Parameter Tractability, Graph Algorithms, Generalization of Trees}
}

Keywords: Graph Contraction, Fixed Parameter Tractability, Graph Algorithms, Generalization of Trees
Collection: 12th International Symposium on Parameterized and Exact Computation (IPEC 2017)
Issue Date: 2018
Date of publication: 02.03.2018


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