We consider the following NP-hard problem: given a connected graph G=(V,ε) and a link set E on V disjoint to ε, find a minimum size subset of edges F ⊆ E such that (V,ε∪F) is 2-edge-connected. In G. Even et al. (2005)  we presented a 1.8-approximation for the problem. In this paper we improve the ratio to 1.5.
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✩ Preliminary version in APPROX 2001, pp. 90–101. * Corresponding author. E-mail addresses: email@example.com (G. Even), firstname.lastname@example.org (G. Kortsarz), email@example.com (Z. Nutov). 1 Partially supported by NSF grant number 0728787.
- Approximation algorithms
- Laminar family
- Tree augmentation