Fixed-parameter tractability of the weighted edge clique partition problem

We develop an FPT algorithm and a compression for the Weighted Edge Clique Partition (WECP) problem, where a graph with n vertices and integer edge weights is given together with an integer k, and the aim is to find k cliques, such that every edge appears in exactly as many cliques as its weight. The problem has been previously only studied in the unweighted version called Edge Clique Partition (ECP), where the edges need to be partitioned into k cliques. It was shown that ECP admits a kernel with k2 vertices [Mujuni and Rosamond, 2008], but this kernel does not extend to WECP. The previously fastest algorithm known for ECP has a runtime of 2O(k2)nO(1) [Issac, 2019]. For WECP we develop a compression (to a slightly more general problem) with 4k vertices, and an algorithm with runtime 2O(k3/2w1/2 log(k/w))nO(1), where w is the maximum edge weight. The latter in particular improves the runtime for ECP to 2O(k3/2 logk)nO(1).