Fixed-Parameter Tractability Results for Feedback Set Problems in Tournaments

摘要

Complementing recent progress on classical complexity and polynomial-time approximability of feedback set problems in (bipartite) tournaments, we extend and partially improve fixed-parameter tractabil-ity results for these problems. We show that FEEDBACK VERTEX SET in tournaments is amenable to the novel iterative compression technique. Moreover, we provide data reductions and problem kernels for FEEDBACK VERTEX SET and FEEDBACK ARC SET in tournaments, and a depth-bounded search tree for FEEDBACK ARC SET in bipartite tournaments based on a new forbidden subgraph characterization.