Graphs of low average degree without independent transversals
dc.contributor.author | Groenland, Carla | |
dc.contributor.author | Kaiser, Tomáš | |
dc.contributor.author | Treffers, Oscar | |
dc.contributor.author | Wales, Matthew | |
dc.date.accessioned | 2023-01-30T11:00:33Z | |
dc.date.available | 2023-01-30T11:00:33Z | |
dc.date.issued | 2023 | |
dc.description.abstract-translated | An independent transversal of a graph G with a vertex partition P is an independent set of G intersecting each block of P in a single vertex. Wanless and Wood proved that if each block of P has size at least t and the average degree of vertices in each block is at most t/4, then an independent transversal of P exists. We present a construction showing that this result is optimal: for any ε>0 and sufficiently large t, there is a family of forests with vertex partitions whose block size is at least t, average degree of vertices in each block is at most (1/4+ε)t, and there is no independent transversal. This unexpectedly shows that methods related to entropy compression such as the Rosenfeld-Wanless-Wood scheme or the Local Cut Lemma are tight for this problem. Further constructions are given for variants of the problem, including the hypergraph version. | en |
dc.format | 14 s. | cs |
dc.format.mimetype | application/pdf | |
dc.identifier.citation | GROENLAND, C. KAISER, T. TREFFERS, O. WALES, M. Graphs of low average degree without independent transversals. Journal of Graph Theory, 2023, roč. 102, č. 2, s. 374-387. ISSN: 0364-9024 | cs |
dc.identifier.document-number | 841136400001 | |
dc.identifier.doi | 10.1002/jgt.22876 | |
dc.identifier.issn | 0364-9024 | |
dc.identifier.obd | 43937771 | |
dc.identifier.uri | 2-s2.0-85135964681 | |
dc.identifier.uri | http://hdl.handle.net/11025/51215 | |
dc.language.iso | en | en |
dc.project.ID | GA20-09525S/Strukturální vlastnosti tříd grafů charakterizovaných zakázanými indukovanými podgrafy | cs |
dc.publisher | Wiley | en |
dc.relation.ispartofseries | Journal of Graph Theory | en |
dc.rights | © authors | en |
dc.rights.access | openAccess | en |
dc.subject.translated | independent transversal | en |
dc.subject.translated | Lovász Local Lemma | en |
dc.subject.translated | entropy compression | en |
dc.title | Graphs of low average degree without independent transversals | en |
dc.type | článek | cs |
dc.type | article | en |
dc.type.status | Peer-reviewed | en |
dc.type.version | publishedVersion | en |
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