# feedback vertex set

## Jones' conjecture ★★

Author(s): Kloks; Lee; Liu

For a graph $G$, let $cp(G)$ denote the cardinality of a maximum cycle packing (collection of vertex disjoint cycles) and let $cc(G)$ denote the cardinality of a minimum feedback vertex set (set of vertices $X$ so that $G-X$ is acyclic).

\begin{conjecture} For every planar graph $G$, $cc(G)\leq 2cp(G)$. \end{conjecture}

Keywords: cycle packing; feedback vertex set; planar graph