Ravishankar Krishnaswamy, Maxim Sviridenko. Inapproximability of the multi-level uncapacitated facility location problem. In Yuval Rabani, editor, Proceedings of the Twenty-Third Annual ACM-SIAM Symposium on Discrete Algorithms, SODA 2012, Kyoto, Japan, January 17-19, 2012. pages 718-734, SIAM, 2012. [doi]
Abstract is missing.