IMO ShortList 1998, combinatorics theory problem 6
Source: IMO ShortList 1998, combinatorics theory problem 6
October 22, 2004
combinatoricspoint setcombinatorial geometryColoringIMO Shortlist
Problem Statement
Ten points are marked in the plane so that no three of them lie on a line. Each pair of points is connected with a segment. Each of these segments is painted with one of colors, in such a way that for any of the ten points, there are segments each joining two of them and no two being painted with the same color. Determine all integers , , for which this is possible.