Albertson–Berman's planar graph feedback vertex set conjecture

Let $G$ be a simple undirected planar graph on $n$ vertices. A feedback vertex set is a set of vertices whose deletion leaves an acyclic graph, and $fvs(G)$ denotes its minimum size.

Albertson–Berman's conjecture.

$$fvs(G)\leq \frac{n}{2}.$$

This is presented as a widely open strengthening of the independent-set consequence of the Four Color Theorem.