Given a graph G = (V, E) and a positive integer k, the PARTITION INTO CLIQUES (PIC) decision problem consists of deciding whether there exists a partition of V into k disjoint subsets V1, V2, . . . , Vk such that the subgraph induced by each part Vi is a complete subgraph (clique) of G. In this paper, we establish both the NP-completeness of PIC for planar cubic graphs and the Max SNP-hardness of PIC for cubic graphs. We present a deterministic polynomial time 5 4 -approximation algorithm for finding clique partitions in maximum degree three graphs. c 2007 Elsevier B.V. All rights reserved.
Márcia R. Cerioli, L. Faria, T. O. Ferreira