Nearest neighbor (k-NN) graphs are widely used in machine learning and data mining applications, and our aim is to better understand what they reveal about the cluster structure of the unknown underlying distribution of points. Moreover, is it possible to identify spurious structures that might arise due to sampling variability?
Our first contribution is a statistical analysis that reveals how certain subgraphs of a k-NN graph form a consistent estimator of the cluster tree of the underlying distribution of points. Our second and perhaps most important contribution is the following finite sample guarantee. We carefully work out the tradeoff between aggressive and conservative pruning and are able to guarantee the removal of all spurious cluster structures at all levels of the tree while at the same time guaranteeing the recovery of salient clusters. This is the first such finite sample result in the context of clustering.
A Nearest Neighbor Characterization of Lebesgue Points in Metric Measure Spaces
Toulouse School of Economics (TSE)(图卢兹经济学院(TSE));Artificial and Natural Intelligence Toulouse Institute (ANITI)(图卢兹人工智能与自然智能研究所(ANITI));Istituto Italiano di Tecnologia(意大利技术研究院);Università degli Studi di Milano(米兰大学)
Department of Statistics, University of California, Berkeley, CA 94720, USA(加州大学伯克利分校统计系);Department of Biostatistics, University of California, Berkeley, CA 94720, USA(加州大学伯克利分校生物统计学系)