论文标题

在没有禁止子图的情况下,存在$ 2 $ factors

Existence of $2$-Factors in Tough Graphs without Forbidden Subgraphs

论文作者

Grimm, Elizabeth, Shan, Songling, Johnsen, Anna

论文摘要

对于给定的图形$ r $,如果$ g $不包含$ r $作为诱导子图,则图$ g $是$ r $ free。众所周知,至少三个顶点的每2 $ tough图都有$ 2 $ - factor。在具有限制结构的图表中,显示出每$ 2K_2 $ - FREE $ 3/2 $ -TOUGH图表至少三个顶点具有$ 2 $ -FACTOR,而韧性约束$ 3/2 $是最好的。在观看$ 2K_2 $的情况下,在本文中,对于5、6或7个顶点的任何线性森林$ r $ $ r $ $ r $ r $的脱节,我们发现每一个尖锐的韧性$ t $,因此,至少三个Vertices上的每个$ t $ r $ r $ r $ r $ - free-free Graph totertion tote toth toter toter toter toth thive tote totertices toter toter toter toter的图形至少有2-属性。

For a given graph $R$, a graph $G$ is $R$-free if $G$ does not contain $R$ as an induced subgraph. It is known that every $2$-tough graph with at least three vertices has a $2$-factor. In graphs with restricted structures, it was shown that every $2K_2$-free $3/2$-tough graph with at least three vertices has a $2$-factor, and the toughness bound $3/2$ is best possible. In viewing $2K_2$, the disjoint union of two edges, as a linear forest, in this paper, for any linear forest $R$ on 5, 6, or 7 vertices, we find the sharp toughness bound $t$ such that every $t$-tough $R$-free graph on at least three vertices has a 2-factor.

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