Vertex rankings of chordal graphs and weighted trees

  • Authors:
  • Dariusz Dereniowski;Adam Nadolski

  • Affiliations:
  • Department of Algorithms and System Modeling, Gdańsk University of Technology, Poland;Department of Algorithms and System Modeling, Gdańsk University of Technology, Poland

  • Venue:
  • Information Processing Letters
  • Year:
  • 2006

Quantified Score

Hi-index 0.89

Visualization

Abstract

In this paper we consider the vertex ranking problem of weighted trees. We show that this problem is strongly NP-hard. We also give a polynomial-time reduction from the problem of vertex ranking of weighted trees to the vertex ranking of (simple) chordal graphs, which proves that the latter problem is NP-hard. In this way we solve an open problem of Aspvall and Heggernes. We use this reduction and the algorithm of Bodlaender et al.'s for vertex ranking of partial k-trees to give an exact polynomial-time algorithm for vertex ranking of a tree with bounded and integer valued weight functions. This algorithm serves as a procedure in designing a PTAS for weighted vertex ranking problem of trees with bounded weight functions.