Enregistré dans:
Détails bibliographiques
Auteurs principaux: Bradshaw, Peter, Mohar, Bojan, Stacho, Ladislav
Format: Preprint
Publié: 2024
Sujets:
Accès en ligne:https://arxiv.org/abs/2409.01513
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  • Alon and Krivelevich conjectured that if $G$ is a bipartite graph of maximum degree $Δ$, then the choosability (or list chromatic number) of $G$ satisfies $χ_{\ell}(G) = O \left ( \log Δ\right )$. Currently, the best known upper bound for $χ_{\ell}(G)$ is $(1 + o(1)) \fracΔ{\log Δ}$, which also holds for the much larger class of triangle-free graphs. We prove that for $\varepsilon = 10^{-3}$, every bipartite graph $G$ of sufficiently large maximum degree $Δ$ satisfies $χ_{\ell}(G) < (\frac{4}{5} -\varepsilon) \fracΔ{\log Δ}$. This improved upper bound suggests that list coloring is fundamentally different for bipartite graphs than for triangle-free graphs and hence gives a step toward solving the conjecture of Alon and Krivelevich.