## Abstract

The multiroot k-outconnected subgraph problem is: given an undirected graph G with nonnegative costs on the edges, a vector of q root nodes R = (r_{1}, ..., r_{q}), and a vector K = (k_{1}, ..., k_{q}) of connectivity requirements (with k = max k_{i}), find a minimum-cost K-outconnected from R spanning subgraph (that is, for every i = 1, ..., q there are k_{i} internally vertex disjoint paths from r_{i} to any other node). The best known algorithm for this problem has approximation ratio 2q, where q can be as large as k-1. For no value of k≥2 a better approximation algorithm is known. We consider the case k_{i}∈{1, 2, 3} which may arise in practical networks. For this case we give a 10/3 -approximation algorithm, improving the best previously known 4-approximation. Our algorithm also implies an improvement for arbitrary k. In the case we have an initial graph which is 2-connected, our algorithm achieves approximation ratio 2.

Original language | English |
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Pages | S951-S952 |

State | Published - 1999 |

Externally published | Yes |

Event | Proceedings of the 1999 10th Annual ACM-SIAM Symposium on Discrete Algorithms - Baltimore, MD, USA Duration: 17 Jan 1999 → 19 Jan 1999 |

### Conference

Conference | Proceedings of the 1999 10th Annual ACM-SIAM Symposium on Discrete Algorithms |
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City | Baltimore, MD, USA |

Period | 17/01/99 → 19/01/99 |