## Abstract

The problem of increasing both edge and vertex connectivity of a graph at an optimal cost is studied. Since the general problem is NP-hard, we focus on efficient approximation schemes that come within a constant factor from the optima]. Previous algorithms either do not take edge costs into consideration, or they run slower than our algorithm. Our algorithm takes as input an undirected graph G_{0} = (V, E_{0}) on n vertices, that is not necessarily connected, and a set Feasible of m weighted edges on V, and outputs a subset Aug of edges which when added to G_{0} make it two-connected. The weight of Aug, when G_{0} is initially connected, is no more than twice the weight of the least weight subset of edges of Feasible that increases the connectivity to two. The running time of our algorithm is O(m + n log n). As a consequence of our results, we can find an approximation to the least-weight two-connected spanning subgraph of a two-connected weighted graph.

Original language | English (US) |
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Pages (from-to) | 214-225 |

Number of pages | 12 |

Journal | Journal of Algorithms |

Volume | 14 |

Issue number | 2 |

DOIs | |

State | Published - Mar 1993 |

## ASJC Scopus subject areas

- Control and Optimization
- Computational Mathematics
- Computational Theory and Mathematics