van den Heuvel, Jan and Král', Daniel and Kupec, Martin and Sereni, Jean-Sébastien and Volec, Jan
(2014)
*Extensions of fractional precolorings show discontinuous behavior.*
Journal of Graph Theory, 77 (4).
pp. 299-329.
ISSN 0364-9024

## Abstract

We study the following problem: given a real number k and an integer d, what is the smallest ε such that any fractional ( k + ε ) -precoloring of vertices at pairwise distances at least d of a fractionally k-colorable graph can be extended to a fractional ( k + ε ) -coloring of the whole graph? The exact values of ε were known for k ϵ {2} ᴜ [3,∞] and any d. We determine the exact values of ε for k ϵ (2,3) if d = 4, and k ϵ [2.5,3) if d = 6, and give upper bounds for k ϵ (2,3) if d = 5,7, and k ϵ (2,2.5) if d = 6. Surprisingly, ε viewed as a function of k is discontinuous for all those values of d.

Item Type: | Article |
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Official URL: | http://onlinelibrary.wiley.com/journal/10.1002/%28... |

Additional Information: | © 2014 Wiley Periodicals, Inc. |

Subjects: | Q Science > QA Mathematics |

Sets: | Departments > Mathematics |

Date Deposited: | 28 Feb 2014 11:25 |

Last Modified: | 15 Jan 2015 13:38 |

URI: | http://eprints.lse.ac.uk/id/eprint/55918 |

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