Corpus ID: 220768974

Half-integral Erd\H{o}s-P\'osa property of directed odd cycles

  title={Half-integral Erd\H\{o\}s-P\'osa property of directed odd cycles},
  author={Ken-ichi Kawarabayashi and Stephan Kreutzer and O-joung Kwon and Qiqin Xie},
  journal={arXiv: Combinatorics},
We prove that there exists a function $f:\mathbb{N}\rightarrow \mathbb{R}$ such that every digraph $G$ contains either $k$ directed odd cycles where every vertex of $G$ is contained in at most two of them, or a vertex set $X$ of size at most $f(k)$ hitting all directed odd cycles. This extends the half-integral Erdős-Posa property of undirected odd cycles, proved by Reed [Mangoes and blueberries. Combinatorica 1999], to digraphs. 

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