Published on *Computer Science Department at Princeton University* (http://www.cs.princeton.edu)

One of the basic geometric operations involves determining whether a pair of convex objects intersect. This problem is well understood in a model of computation where the objects are given as input and their intersection is returned as output. For many applications, however, we may assume that the objects already exist within the computer and that the only output desired is a single piece of data giving a common point if the objects intersect, or reporting no intersection if they are disjoint. For this problem, none of the previous lower bounds are valid and we propose algorithms requiring sublinear time for their solution in two and three dimensions.