A Note on the Approximation of a Minimum-Weight Maximal Independent Set

  • Authors:
  • Marc Demange

  • Affiliations:
  • CERMSEM, Université Paris I, Maison des Sciences Economiques, 106-112, Boulevard de l‘Hôpital, 75647 Paris Cedex 13, France and LAMSADE, Université Paris-Dauphine, Place du Ma ...

  • Venue:
  • Computational Optimization and Applications
  • Year:
  • 1999

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Abstract

We consider the polynomial approximationbehavior of the problem of finding, in a graphwith weighted vertices, a maximal independent setminimizing the sum of the weights. In the spirit of a work ofHalldórson dealing with the unweighted case, weextend it and perform approximation hardness results by using areduction from the minimum coloring problem. In particular, aconsequence of our main result is that there does not exist anypolynomial time algorithm approximating this problem within a ratioindependent of the weights, unless P = NP. We bring also to the fore avery simple ratio ρ guaranteed by every algorithm while nopolynomial time algorithm can guarantee the ratio (1 − ε)ρ.The known hardness results for the unweighted case can be deduced. Wefinally discuss approximation results for both weighted andunweighted cases: we perform an approximation ratio that is valid forany algorithm for the former and propose an analysis of a greedyalgorithm for the latter.