Lower bounds for the smoothed number of pareto optimal solutions

  • Authors:
  • Tobias Brunsch;Heiko Röglin

  • Affiliations:
  • Department of Computer Science, University of Bonn, Germany;Department of Computer Science, University of Bonn, Germany

  • Venue:
  • TAMC'11 Proceedings of the 8th annual conference on Theory and applications of models of computation
  • Year:
  • 2011

Quantified Score

Hi-index 0.02

Visualization

Abstract

In 2009, Röglin and Teng showed that the smoothed number of Pareto optimal solutions of linear multi-criteria optimization problems is polynomially bounded in the number n of variables and the maximum density Ø of the semi-random input model for any fixed number of objective functions. Their bound is, however, not very practical because the exponents grow exponentially in the number d+1 of objective functions. In a recent breakthrough, Moitra and O'Donnell improved this bound significantly to O(n2dØd(d+1)/2). An "intriguingproblem", which Moitra and O'Donnell formulate intheir paper, is how much further this bound can be improved. The previous lower bounds do not exclude the possibility of a polynomial upper bound whose degree does not depend on d. In this paper we resolve this question by constructing a class of instances with Ω((nØ)(d-log(d))ċ(1-Θ(1/Ø))) Pareto optimal solutions in expectation. For the bi-criteria case we present a higher lower bound of Ω(n2Ø1-Θ(1/Ø)), which almost matches the known upper bound of O(n2Ø).