An Improved Kernel for Planar Connected Dominating Set

Weizhong Luo, Jianxin Wang, Qilong Feng, Jiong Guo, Jianer Chen

Abstract: In this paper, we study the Planar Connected Dominating Set problem, which, given a planar graph G = (V,E) and a non-negative integer k, asks for a subset D ⊆ V with |D| ≤ k such that D forms a dominating set of G and induces a connected graph. Answering an open question by S. Saurabh [The 2nd Workshop on Kernelization (WorKer 2010)], we provide a kernelization algorithm for this problem leading to a problem kernel with 130k vertices, significantly improving the previously best upper bound on the kernel size. To this end, we incorporate a vertex coloring technique with data reduction rules and introduce for the first time a distinction of two types of regions into the region decomposition framework, which allows a refined analysis of the region size and could be used to reduce the kernel sizes achieved by the region decomposition technique for a large range of problems.