On the Complexity of the Circular Chromatic Number

dc.creatorHatami, Hamed
dc.creatorTusserkani, Ruzbeh
dc.date2006-12-31
dc.date.accessioned2026-07-07T07:37:52Z
dc.date.available2026-07-07T07:37:52Z
dc.descriptionCircular chromatic number, $χ_c$ is a natural generalization of chromatic number. It is known that it is \NP-hard to determine whether or not an arbitrary graph $G$ satisfies $χ(G) = χ_c(G)$. In this paper we prove that this problem is \NP-hard even if the chromatic number of the graph is known. This answers a question of Xuding Zhu. Also we prove that for all positive integers $k \ge 2$ and $n \ge 3$, for a given graph $G$ with $χ(G)=n$, it is \NP-complete to verify if $χ_c(G) \le n- \frac{1}{k}$.
dc.identifierhttps://arxiv.org/abs/cs/0701007
dc.identifierhttp://arxiv.org/abs/cs/0701007
dc.identifierJournal of Graph Theory. 47(3) (2004) pp. 226-230
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/120925
dc.subjectComputational Geometry
dc.titleOn the Complexity of the Circular Chromatic Number
dc.typetext

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