An improved bound for the linear arboricity conjecture

In 1980, Akiyama, Exoo and Harary posited the Linear Arboricity Conjecture which states that any graph G of maximum degree can be decomposed into at most ¿ 2 ¿ linear forests. (A forest is linear if all of its components are paths.) In 1988, Alon proved the conjecture holds asymptotically. The curre...

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Detalles Bibliográficos
Autores: Postle, Luke, Lang, Richard Johannes|||0000-0002-7661-934X
Tipo de recurso: artículo
Fecha de publicación:2023
País:España
Institución:Universitat Politècnica de Catalunya (UPC)
Repositorio:UPCommons. Portal del coneixement obert de la UPC
Idioma:inglés
OAI Identifier:oai:upcommons.upc.edu:2117/459364
Acceso en línea:https://hdl.handle.net/2117/459364
https://dx.doi.org/10.1007/s00493-023-00024-9
Access Level:acceso abierto
Palabra clave:Graph colouring
List colouring
Edge colouring
Linear arboricity
Classificació AMS::05 Combinatorics::05C Graph theory
Àrees temàtiques de la UPC::Matemàtiques i estadística::Lògica matemàtica
Descripción
Sumario:In 1980, Akiyama, Exoo and Harary posited the Linear Arboricity Conjecture which states that any graph G of maximum degree can be decomposed into at most ¿ 2 ¿ linear forests. (A forest is linear if all of its components are paths.) In 1988, Alon proved the conjecture holds asymptotically. The current best bound is due to Ferber, Fox and Jain from 2020 who showed that 2 + O( 0.661) suffices for large enough . Here, we show that G admits a decomposition into at most 2 + 3v log 4 linear forests provided is large enough. Moreover, our result also holds in the more general list setting, where edges have (possibly different) sets of permissible linear forests. Thus our bound also holds for the List Linear Arboricity Conjecture which was only recently shown to hold asymptotically by Kim and the second author. Indeed, our proof method ties together the Linear Arboricity Conjecture and the well-known List Colouring Conjecture; consequently, our error term for the Linear Arboricity Conjecture matches the best known error-term for the List Colouring Conjecture due to Molloy and Reed from 2000. This follows as we make two copies of every colour and then seek a proper edge colouring where we avoid bicoloured cycles between a colour and its copy; we achieve this via a clever modification of the nibble method.