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arXiv math/0512518math.CO
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无邻3-圈的可平面图的边可选性和全可选性

Edge-choosability and total-choosability of planar graphs with no adjacent 3-cycles

Daniel W. Cranston

摘要:

设$G$是一个平面图,没有两个3-圈共享一条边。我们还证明了,如果$Δ(G)\geq 9$,则$χ'_l(G) = Δ(G)$和$χ''_l(G)=Δ(G)+1.$,如果$Δ(G)\geq 6$,则$χ'_l(G)\leqΔ(G)+1$,如果$Δ(G)\geq 7$,则$χ''_l(G)\leqΔ(G)+2$。所有这些结果都推广到了射影平面上的图,当$Δ(G)\geq 7$的结果也推广到了环面和克莱因瓶上的图。这第二个边可选性结果改进了Wang和Lih以及Zhang和Wu的工作。我们的所有结果都是用放电方法证明了关于度和小的子图存在性的结构引理。例如,我们证明了如果$G$是一个平面图,没有两个3-圈共享一个边,并与$Δ(G)\geq 7$,那么$G$有一个边$uv$与$d(u)\leq 4$和$d(u)+d(v)\leq Δ(G)+2$。我们所有的证明产生线性时间算法,产生所需的着色。

英文摘要:

Let $G$ be a planar graph with no two 3-cycles sharing an edge. We show that if $Δ(G)\geq 9$, then $χ'_l(G) = Δ(G)$ and $χ''_l(G)=Δ(G)+1.$ We also show that if $Δ(G)\geq 6$, then $χ'_l(G)\leqΔ(G)+1$ and if $Δ(G)\geq 7$, then $χ''_l(G)\leqΔ(G)+2$. All of these results extend to graphs in the projective plane and when $Δ(G)\geq 7$ the results also extend to graphs in the torus and Klein bottle. This second edge-choosability result improves on work of Wang and Lih and of Zhang and Wu. All of our results use the discharging method to prove structural lemmas about the existence of subgraphs with small degree-sum. For example, we prove that if $G$ is a planar graph with no two 3-cycles sharing an edge and with $Δ(G)\geq 7$, then $G$ has an edge $uv$ with $d(u)\leq 4$ and $d(u)+d(v)\leq Δ(G)+2$. All of our proofs yield linear-time algorithms that produce the desired colorings.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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