Improved approximations for the Steiner tree problem
SODA '92 Proceedings of the third annual ACM-SIAM symposium on Discrete algorithms
STOC '97 Proceedings of the twenty-ninth annual ACM symposium on Theory of computing
A threshold of ln n for approximating set cover
Journal of the ACM (JACM)
On the bidirected cut relaxation for the metric Steiner tree problem
Proceedings of the tenth annual ACM-SIAM symposium on Discrete algorithms
Approximating the weight of shallow Steiner trees
Discrete Applied Mathematics
Approximation algorithms for directed Steiner problems
Journal of Algorithms
SODA '02 Proceedings of the thirteenth annual ACM-SIAM symposium on Discrete algorithms
Improved approximations for tour and tree covers
APPROX '00 Proceedings of the Third International Workshop on Approximation Algorithms for Combinatorial Optimization
Polylogarithmic inapproximability
Proceedings of the thirty-fifth annual ACM symposium on Theory of computing
Tighter Bounds for Graph Steiner Tree Approximation
SIAM Journal on Discrete Mathematics
The Steiner tree problem on graphs: Inapproximability results
Theoretical Computer Science
An improved LP-based approximation for steiner tree
Proceedings of the forty-second ACM symposium on Theory of computing
Approximation algorithm for the minimum directed tree cover
COCOA'10 Proceedings of the 4th international conference on Combinatorial optimization and applications - Volume Part II
How to trim an MST: a 2-approximation algorithm for minimum cost tree cover
ICALP'06 Proceedings of the 33rd international conference on Automata, Languages and Programming - Volume Part I
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We present a greedy algorithm for the directed Steiner tree problem (DST), where any tree rooted at any (uncovered) terminal can be a candidate for greedy choice. It will be shown that the algorithm, running in polynomial time for any constant l, outputs a directed Steiner tree of cost no larger than 2(l−1)(ln n+1) times the cost of the minimum l-restricted Steiner tree. We derive from this result that 1) DST for a class of graphs, including quasi-bipartite graphs, in which the length of paths induced by Steiner vertices is bounded by some constant can be approximated within a factor of O(logn), and 2) the tree cover problem on directed graphs can also be approximated within a factor of O(logn).