A better approximation ratio for the vertex cover problem

  • Authors:
  • George Karakostas

  • Affiliations:
  • Department of Computing and Software, McMaster University

  • Venue:
  • ICALP'05 Proceedings of the 32nd international conference on Automata, Languages and Programming
  • Year:
  • 2005

Quantified Score

Hi-index 0.00

Visualization

Abstract

We reduce the approximation factor for Vertex Cover to $2 - \theta(\frac{1}{\sqrt{{\rm log} n}})$ (instead of the previous $2- \theta(\frac{{\rm log log} n}{{\rm log}\ n})$, obtained by Bar-Yehuda and Even [3], and by Monien and Speckenmeyer[11]). The improvement of the vanishing factor comes as an application of the recent results of Arora, Rao, and Vazirani [2] that improved the approximation factor of the sparsest cut and balanced cut problems. In particular, we use the existence of two big and well-separated sets of nodes in the solution of the semidefinite relaxation for balanced cut, proven in [2]. We observe that a solution of the semidefinite relaxation for vertex cover, when strengthened with the triangle inequalities, can be transformed into a solution of a balanced cut problem, and therefore the existence of big well-separated sets in the sense of [2] translates into the existence of a big independent set.