Cops and robbers on $P_5$-free graphs
Maria Chudnovsky, Sergey Norin, Paul D. Seymour, Jérémie Turcotte · arXiv (Cornell University) · 2023
We prove that every connected $P_5$-free graph has cop number at most two, solving a conjecture of Sivaraman. In order to do so, we first prove that every connected $P_5$-free graph $G$ with independence number at least three contains a three-vertex induced path with vertices $a \hbox{-} b \hbox{-} c$ in order, such that every neighbour of $c$ is also adjacent to one of $a,b$.