Smaller coresets for k-median and k-means clustering

In this paper, we show that there exists a (k, ε)-coreset for k-median and k-means clustering of n points in Rd, which is of size independent of n. In particular, we construct a (k, ε)-coreset of size O(k2/εd) for k-median clustering, and of size O(k3/εd+1) for k-means clustering.