On toughness and hamiltonicity of 2K2-free graphs

Haitze J. Broersma, Viresh Patel, Artem Pyatkin

Research output: Contribution to journalArticleAcademicpeer-review

4 Citations (Scopus)

Abstract

The toughness of a (noncomplete) graph G is the minimum value of t for which there is a vertex cut A whose removal yields |A|/t components. Determining toughness is an NP-hard problem for general input graphs. The toughness conjecture of Chvátal, which states that there exists a constant t such that every graph on at least three vertices with toughness at least t is hamiltonian, is still open for general graphs. We extend some known toughness results for split graphs to the more general class of 2K2-free graphs, that is, graphs that do not contain two vertex-disjoint edges as an induced subgraph. We prove that the problem of determining toughness is polynomially solvable and that Chvátal's toughness conjecture is true for 2K2-free graphs.
Original languageUndefined
Pages (from-to)244-255
Number of pages12
JournalJournal of graph theory
Volume75
Issue number3
DOIs
Publication statusPublished - Mar 2014

Keywords

  • EWI-24563
  • MSC-05C
  • Forbidden subgraph
  • Hamiltonian graph
  • Toughness
  • t-Tough graph
  • METIS-305860
  • IR-89614
  • 2K2-free graph

Cite this

Broersma, Haitze J. ; Patel, Viresh ; Pyatkin, Artem. / On toughness and hamiltonicity of 2K2-free graphs. In: Journal of graph theory. 2014 ; Vol. 75, No. 3. pp. 244-255.
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On toughness and hamiltonicity of 2K2-free graphs. / Broersma, Haitze J.; Patel, Viresh; Pyatkin, Artem.

In: Journal of graph theory, Vol. 75, No. 3, 03.2014, p. 244-255.

Research output: Contribution to journalArticleAcademicpeer-review

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T1 - On toughness and hamiltonicity of 2K2-free graphs

AU - Broersma, Haitze J.

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AB - The toughness of a (noncomplete) graph G is the minimum value of t for which there is a vertex cut A whose removal yields |A|/t components. Determining toughness is an NP-hard problem for general input graphs. The toughness conjecture of Chvátal, which states that there exists a constant t such that every graph on at least three vertices with toughness at least t is hamiltonian, is still open for general graphs. We extend some known toughness results for split graphs to the more general class of 2K2-free graphs, that is, graphs that do not contain two vertex-disjoint edges as an induced subgraph. We prove that the problem of determining toughness is polynomially solvable and that Chvátal's toughness conjecture is true for 2K2-free graphs.

KW - EWI-24563

KW - MSC-05C

KW - Forbidden subgraph

KW - Hamiltonian graph

KW - Toughness

KW - t-Tough graph

KW - METIS-305860

KW - IR-89614

KW - 2K2-free graph

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