论文标题

归化图的线性树木

Linear arboricity of degenerate graphs

论文作者

Chen, Guantao, Hao, Yanli, Yu, Guoning

论文摘要

线性森林是顶点 - 偶口路径的结合,图$ g $的线性树木均由$ \ operatatorName {la}(g)$表示,是将$ g $的边缘套件划分的最低线性森林数量。显然,$ \ operatorname {la}(g)\ ge \lceilδ(g)/2 \ rceil $ for Graph $ g $,最高度$δ(g)$。另一方面,由于Akiyama,Exoo和Harary引起的线性树木猜想,自1981年以来断言$ \ operatatorName {la}(g)(g)\ leq \ lceil(δ(g)+1 +1) / 2 \ rceil $ for每图$ g $。该猜想已被验证用于平面图和图形最高学位最多$ 6 $,或等于$ 8 $或$ 10 $的平面图和图形。 考虑到一个正整数$ k $,如果可以通过连续删除最多$ k $的顶点,则图表$ g $是$ k $ degenate,如果可以将其简化为琐碎的图。我们证明,对于任何$ k $ -DECENATER GRAPH $ g $,$ \ operatatorName {la}(g)= \lceilΔ(g)/2 \ rceil $提供$δ(g)\ ge 2k^2 -k $。

A linear forest is a union of vertex-disjoint paths, and the linear arboricity of a graph $G$, denoted by $\operatorname{la}(G)$, is the minimum number of linear forests needed to partition the edge set of $G$. Clearly, $\operatorname{la}(G) \ge \lceilΔ(G)/2\rceil$ for a graph $G$ with maximum degree $Δ(G)$. On the other hand, the Linear Arboricity Conjecture due to Akiyama, Exoo, and Harary from 1981 asserts that $\operatorname{la}(G) \leq \lceil(Δ(G)+1) / 2\rceil$ for every graph $ G $. This conjecture has been verified for planar graphs and graphs whose maximum degree is at most $ 6 $, or is equal to $ 8 $ or $ 10 $. Given a positive integer $k$, a graph $G$ is $k$-degenerate if it can be reduced to a trivial graph by successive removal of vertices with degree at most $k$. We prove that for any $k$-degenerate graph $G$, $\operatorname{la}(G) = \lceilΔ(G)/2 \rceil$ provided $Δ(G) \ge 2k^2 -k$.

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