We apply Megiddo's parametric searching technique to several geometric
optimization problems and derive significantly improved solutions for
them. We obtain, for any fixed epsilon > 0, an O(n1+epsilon) algorith
m for computing the diameter of a point set in 3-space, an O(8/5+epsil
on) algorithm for computing the width of such a set, and an O(n8/5+eps
ilon) algorithm for computing the closest pair in a set of n lines in
space. All these algorithms are deterministic.