A simple 7/3-approximation algorithm for feedback vertex set in tournaments

Abstract

We show that performing just one round of the Sherali-Adams hierarchy gives an easy 7/3-approximation algorithm for the Feedback Vertex Set (FVST) problem in tournaments. This matches the best deterministic approximation algorithm for FVST due to Mnich, Williams, and V\'egh, and is a significant simplification and runtime improvement of their approach.