Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site uwvax.UUCP Path: utzoo!watmath!clyde!burl!ulysses!allegra!mit-eddie!godot!harvard!seismo!uwvax!anderson From: anderson@uwvax.UUCP (David P. Anderson) Newsgroups: net.puzzle,net.math Subject: Another neat problem from Putnam Exam Message-ID: <10@uwvax.UUCP> Date: Sat, 20-Oct-84 02:41:14 EDT Article-I.D.: uwvax.10 Posted: Sat Oct 20 02:41:14 1984 Date-Received: Sun, 21-Oct-84 14:47:17 EDT Distribution: net Organization: U of Wisconsin CS Dept Lines: 13 Xref: godot net.puzzle:240 net.math:494 <> This is one of my favorites. You have sets X and Y of points in the plane, each with n elements. Assume that no three points in X u Y are colinear. Prove or give a counterexample: there is a set of line segments, each of which has one endpoint in X and the other in Y, and of which any two segments are disjoint. Hint: the solution is simple and doesn't use any geometry outside of the triangle inequality. David Anderson (uwvax!anderson)