2004/01/01 by Guy Kortsarz, Robert Krauthgamer, James R. Lee · 8 citations
Computer Science · #Complexity and Algorithms in Graphs #Advanced Graph Theory Research #Optimization and Search Problems
paper · doi:10.1137/s0097539702416736
In the survivable networkdesign problem (SNDP), the goal is to find a minimum-cost spanning subgraph satisfying certain connectivity requirements. We study the vertex-connectivity variant of SNDP in which the input specifies, for each pair of vertices, a required number of vertex-disjoint paths connecting them. We give the first strong lower bound on the approximability of SNDP, showing that the problem admits no efficient 2^log1-ε n ratio approximation for any fixed ε > 0, unless \NP⊆ \DTIME(n\polylog(n)). We show hardness of approximation results for some important special cases of SNDP, and we exhibit the first lower bound on the approximability of the related classical NP-hard problem of augmenting the connectivity of a graph using edges from a given set.