We show that the standard linear programming relaxation for the tree augmentation problem in undirected graphs has an integrality ratio that approaches 3 2 . This refutes a conjec...
Joseph Cheriyan, Howard J. Karloff, Rohit Khandeka...
The natural relaxation for the Group Steiner Tree problem, as well as for its generalization, the Directed Steiner Tree problem, is a flow-based linear programming relaxation. We...
Eran Halperin, Guy Kortsarz, Robert Krauthgamer, A...