论文标题

走向小的准内核猜想

Towards the Small Quasi-Kernel Conjecture

论文作者

Kostochka, Alexandr, Luo, Ruth, Shan, Songling

论文摘要

令$ d =(v,a)$为挖掘物。如果$ k $是$ d $中的独立套件,则顶点$ k \ subseteq v $是$ d $的准内核,对于每个v \ setminus k $ in v \ setminus k $,$ v $的每个顶点$ v \,最多是$ k $的2。 1974年,Chvátal和Lovász证明了每个Digraph都有准内核。 P. L.Erdős和L. A.Székely在1976年猜想,如果每个顶点$ d $都有正化,则$ d $的大小为$ | v |/2 $。该猜想仅用于狭窄类别的狭窄类别,例如半完整的多部分,准传播或局部分离的挖掘。在本说明中,我们陈述了所有digraphs的类似猜想,表明这两个猜想是等效的,并证明了两个猜想对包含所有4色图的所有方向(尤其是所有平面图)的一类挖掘物。

Let $D=(V,A)$ be a digraph. A vertex set $K\subseteq V$ is a quasi-kernel of $D$ if $K$ is an independent set in $D$ and for every vertex $v\in V\setminus K$, $v$ is at most distance 2 from $K$. In 1974, Chvátal and Lovász proved that every digraph has a quasi-kernel. P. L. Erdős and L. A. Székely in 1976 conjectured that if every vertex of $D$ has a positive indegree, then $D$ has a quasi-kernel of size at most $|V|/2$. This conjecture is only confirmed for narrow classes of digraphs, such as semicomplete multipartite, quasi-transitive, or locally demicomplete digraphs. In this note, we state a similar conjecture for all digraphs, show that the two conjectures are equivalent, and prove that both conjectures hold for a class of digraphs containing all orientations of 4-colorable graphs (in particular, of all planar graphs).

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