kNN query 1-NN query of has true answer Applying 1-NN on l projections gives l collision sets:   2,9,13:   7,10,14:   1,5,11:   8,12,14: Now majority counting gives No guarantee of correct answer Accuracy increases with more runs It can be proved that is approximately distance preserving provided is so ( already is so!) Therefore, this is a Monte Carlo algorithm Time: where is the dimensionality (here, 3) Extensions for Euclidean space: E2LSH