Improved approximation algorithms for optimization problems in graphs with superlogarithmic treewidth

Abstract

In this paper we present two novel generic schemes for approximation algorithms for optimization NP-hard graph problems constrained to partial k-trees. Our first scheme yields deterministic polynomial-time algorithms achieving typically an approximation factor of k/log1-∈ n, where k = polylog(n). The second scheme yields randomized polynomial-time algorithms achieving an approximation factor of k/logn for k = Ω(log n). Both our approximation methods lead to the best known approximation guarantees for some basic optimization problems. In particular, we obtain best known polynomial-time approximation guarantees for the classical maximum independent set problem in partial trees. © Springer-Verlag Berlin Heidelberg 2003.