A Quadratic Kernel for {Claw, Diamond}-free Deletion
摘要
The {claw, diamond}-free edge deletion problem admits an \(O(k^3)\) -vertex kernel [Theoretical Computer Science 2022]. In this paper, we improve it to \(O(k^2)\) vertices. We use the modulator technique and then bound the number of vertices outside the modulator. Let M be an arbitrary modulator. We find that, the propagation between the maximal cliques in \(G-M\) is always due to the claw graph. Based on the observation, the number of vertices in the maximal cliques untouched to M can be bounded by \(O(k^2)\) . Since \(|M|=O(k)\) and the maximal cliques in \(G-M\) touched to M is bounded by some normal kernel frameworks, we thus have the claimed kernelization size.