Given an undirected graph, finding either a minimum 2-edge-connected spanning subgraph or a minimum 2vertex-connected (biconnected) spanning subgraph is MaxSNP-hard. We show that ...
Artur Czumaj, Michelangelo Grigni, Papa Sissokho, ...
We consider the Minimum Linear Arrangement problem and the (Uniform) Sparsest Cut problem. So far, these two notorious NP-hard graph problems have resisted all attempts to prove in...
We design polynomial time approximation schemes (PTASs) for Metric BISECTION, i.e. dividing a given finite metric space into two halves so as to minimize or maximize the sum of di...
Wenceslas Fernandez de la Vega, Marek Karpinski, C...
Given an undirected multigraph G and a subset of vertices S V (G), the STEINER TREE PACKING problem is to find a largest collection of edge-disjoint trees that each connects S. T...
We study complexity and approximation of min weighted node coloring in planar, bipartite and split graphs. We show that this problem is NP-complete in planar graphs, even if they a...