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.ITCS.2021.4
URN: urn:nbn:de:0030-drops-135431
URL: http://dagstuhl.sunsite.rwth-aachen.de/volltexte/2021/13543/
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Haviv, Ishay

The Complexity of Finding Fair Independent Sets in Cycles

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LIPIcs-ITCS-2021-4.pdf (0.5 MB)

Abstract

Let G be a cycle graph and let V₁,…,V_m be a partition of its vertex set into m sets. An independent set S of G is said to fairly represent the partition if |S ∩ V_i| ≥ 1/2⋅|V_i| - 1 for all i ∈ [m]. It is known that for every cycle and every partition of its vertex set, there exists an independent set that fairly represents the partition (Aharoni et al., A Journey through Discrete Math., 2017). We prove that the problem of finding such an independent set is PPA-complete. As an application, we show that the problem of finding a monochromatic edge in a Schrijver graph, given a succinct representation of a coloring that uses fewer colors than its chromatic number, is PPA-complete as well. The work is motivated by the computational aspects of the "cycle plus triangles" problem and of its extensions.

BibTeX - Entry

@InProceedings{haviv:LIPIcs.ITCS.2021.4,
  author =	{Ishay Haviv},
  title =	{{The Complexity of Finding Fair Independent Sets in Cycles}},
  booktitle =	{12th Innovations in Theoretical Computer Science Conference (ITCS 2021)},
  pages =	{4:1--4:14},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-177-1},
  ISSN =	{1868-8969},
  year =	{2021},
  volume =	{185},
  editor =	{James R. Lee},
  publisher =	{Schloss Dagstuhl--Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/opus/volltexte/2021/13543},
  URN =		{urn:nbn:de:0030-drops-135431},
  doi =		{10.4230/LIPIcs.ITCS.2021.4},
  annote =	{Keywords: Fair independent sets in cycles, the complexity class \{PPA\}, Schrijver graphs}
}

Keywords: Fair independent sets in cycles, the complexity class {PPA}, Schrijver graphs
Collection: 12th Innovations in Theoretical Computer Science Conference (ITCS 2021)
Issue Date: 2021
Date of publication: 04.02.2021

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