Digraphs with All Induced Directed Cycles of the Same Length are not → χ -Bounded

dc.contributor.authorCarbonero, Alvaro
dc.contributor.authorHompe, Patrick
dc.contributor.authorMoore, Benjamin
dc.contributor.authorSpirkl, Sophie
dc.date.accessioned2022-10-17T16:21:38Z
dc.date.available2022-10-17T16:21:38Z
dc.date.issued2022-10-07
dc.description.abstractFor t > 2, let us call a digraph D t-chordal if all induced directed cycles in D have length equal to t. In an earlier paper, we asked for which t it is true that t-chordal graphs with bounded clique number have bounded dichromatic number. Recently, Aboulker, Bousquet, and de Verclos answered this in the negative for t = 3, that is, they gave a construction of 3-chordal digraphs with clique number at most 3 and arbitrarily large dichromatic number. In this paper, we extend their result, giving for each t > 3 a construction of t-chordal digraphs with clique number at most 3 and arbitrarily large dichromatic number, thus answering our question in the negative. On the other hand, we show that a more restricted class, digraphs with no induced directed cycle of length less than t, and no induced directed t-vertex path, have bounded dichromatic number if their clique number is bounded. We also show the following complexity result: for fixed t > 2, the problem of determining whether a digraph is t-chordal is coNP-complete.en
dc.description.sponsorshipThis research was supported by the Natural Sciences and Engineering Research Council of Canada (NSERC), RGPIN-2020-03912.en
dc.identifier.urihttps://doi.org/10.37236/11179
dc.identifier.urihttp://hdl.handle.net/10012/18888
dc.language.isoenen
dc.relation.ispartofseriesElectronic Journal of Combinatorics;
dc.rightsAttribution 4.0 International*
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/*
dc.titleDigraphs with All Induced Directed Cycles of the Same Length are not → χ -Boundeden
dc.typeArticleen
dcterms.bibliographicCitationCarbonero, A., Hompe, P., Moore, B., & Spirkl, S. (2022). Digraphs with All Induced Directed Cycles of the Same Length are not → χ -Bounded. Electronic Journal of Combinatorics, 29(4). https://doi.org/https://doi.org/10.37236/11179en
uws.contributor.affiliation1Faculty of Mathematicsen
uws.contributor.affiliation2Combinatorics and Optimizationen
uws.peerReviewStatusRevieweden
uws.scholarLevelFacultyen
uws.typeOfResourceTexten

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