The Reverse Greedy algorithm (RGREEDY) for the k-median problem works as follows. It starts by placing facilities on all nodes. At each step, it removes a facility to minimize the total distance to the remaining facilities. It stops when k facilities remain. We prove that, if the distance function is metric, then the approximation ratio of RGREEDY is between (logn/loglogn) and O(logn). 2005 Elsevier B.V. All rights reserved.
Marek Chrobak, Claire Kenyon, Neal E. Young