Essentially Tight Kernels For (Weakly) Closed Graphs

Autor: Tomohiro Koana, Christian Komusiewicz, Frank Sommer
Jazyk: angličtina
Rok vydání: 2021
Předmět:
DOI: 10.4230/lipics.isaac.2021.35
Popis: We study kernelization of classic hard graph problems when the input graphs fulfill triadic closure properties. More precisely, we consider the recently introduced parameters closure number c and weak closure number �� [Fox et al., SICOMP 2020] in addition to the standard parameter solution size k. The weak closure number �� of a graph is upper-bounded by the minimum of its closure number c and its degeneracy d. For Capacitated Vertex Cover, Connected Vertex Cover, and Induced Matching we obtain the first kernels of size k^����(��), k^����(��), and (��k)^����(��), respectively. This extends previous results on the kernelization of these problems on degenerate graphs. These kernels are essentially tight as these problems are unlikely to admit kernels of size k^o(��) by previous results on their kernelization complexity in degenerate graphs [Cygan et al., ACM TALG 2017]. For Capacitated Vertex Cover, we show that even a kernel of size k^o(c) is unlikely. In contrast, for Connected Vertex Cover, we obtain a problem kernel with ����(ck��) vertices. Moreover, we prove that searching for an induced subgraph of order at least k belonging to a hereditary graph class ���� admits a kernel of size k^����(��) when ���� contains all complete and all edgeless graphs. Finally, we provide lower bounds for the kernelization of Independent Set on graphs with constant closure number c and kernels for Dominating Set on weakly closed split graphs and weakly closed bipartite graphs.
LIPIcs, Vol. 212, 32nd International Symposium on Algorithms and Computation (ISAAC 2021), pages 35:1-35:15
Databáze: OpenAIRE