On the tightness of an SDP relaxation of k-means

Recently, [3] introduced an SDP relaxation of the k-means problem in R. In this work, we consider a random model for the data points in which k balls of unit radius are deterministically distributed throughout R, and then in each ball, n points are drawn according to a common rotationally invariant probability distribution. For any fixed ball configuration and probability distribution, we prove that the SDP relaxation of the k-means problem exactly recovers these planted clusters with probability 1− e−Ω(n) provided the distance between any two of the ball centers is > 2 + , where is an explicit function of the configuration of the ball centers, and can be arbitrarily small when m is large.