论文标题
定向射线的普及
Ubiquity of oriented rays
论文作者
论文摘要
如果每个digraph $ d $包含$ k $ tertex-dischoint副本$ h $ in \ mathbb {n} $都包含$ h $ $ h $ $ h $，则调用Digraph $ h $ \ emph {ubiquitous}。我们表征了哪些基本无向图的挖掘物无处不在。
Call a digraph $H$ \emph{ubiquitous} if every digraph $D$ that contains $k$ vertex-disjoint copies of $H$ for every $k \in \mathbb{N}$ also contains infinitely many vertex-disjoint copies of $H$. We characterise which digraphs whose underlying undirected graph is a ray are ubiquitous.
