English

Linear-time Algorithms for Eliminating Claws in Graphs

Data Structures and Algorithms 2023-10-06 v1

Abstract

Since many NP-complete graph problems have been shown polynomial-time solvable when restricted to claw-free graphs, we study the problem of determining the distance of a given graph to a claw-free graph, considering vertex elimination as measure. CLAW-FREE VERTEX DELETION (CFVD) consists of determining the minimum number of vertices to be removed from a graph such that the resulting graph is claw-free. Although CFVD is NP-complete in general and recognizing claw-free graphs is still a challenge, where the current best algorithm for a graph GG has the same running time of the best algorithm for matrix multiplication, we present linear-time algorithms for CFVD on weighted block graphs and weighted graphs with bounded treewidth. Furthermore, we show that this problem can be solved in linear time by a simpler algorithm on forests, and we determine the exact values for full kk-ary trees. On the other hand, we show that CLAW-FREE VERTEX DELETION is NP-complete even when the input graph is a split graph. We also show that the problem is hard to approximate within any constant factor better than 22, assuming the Unique Games Conjecture.

Keywords

Cite

@article{arxiv.2004.05672,
  title  = {Linear-time Algorithms for Eliminating Claws in Graphs},
  author = {Flavia Bonomo-Braberman and Julliano R. Nascimento and Fabiano S. Oliveira and Uéverton S. Souza and Jayme L. Szwarcfiter},
  journal= {arXiv preprint arXiv:2004.05672},
  year   = {2023}
}

Comments

20 pages

R2 v1 2026-06-23T14:48:40.463Z