Table 3: Related work on augmenting link connectivity in unweighted graphs.

Year Reference Complexity Description 1976 Eswaran and Tarjan [54] Augmenting to 2-connectivity. 1986 Cai and Sun [75] NA Splitting off links. 1987 Watanabe and Nakamura [76] Based on a derived formula for the minimum number of links to -link-connect . 1990 Frank [77] Different s-t connectivities may be specified, instead of one -connectivity for all pairs1. 1990 Naor et al. [65] is the complexity of computing a maximum flow. If , then the complexity is . 1991 Gabow [78] Poset representation of cuts applied to the Naor-Gusfield-Martel algorithm. 1994 Benczúr [79] , Resp. randomized and deterministic algorithms. 1996 Nagamochi and Ibaraki [80] Splitting off links. 1998 Benczúr and Karger [81] Randomized algorithm. 2004 Nagamochi and Ibaraki [82] Maximum adjacency ordering2.

1NP-hard variations of this problem and corresponding approximation results are provided by Nutov [83]. 2Maximum adjacency ordering rule: add a new node to previously selected nodes that has the largest number of links to the set . Start with an abitrary node .