Coloring 100 x 100 array of points in four colors
Source: ARMO 2000
March 12, 2008
LaTeXcombinatorics unsolvedcombinatorics
Problem Statement
All points in a array are colored in one of four colors red, green, blue or yellow in such a way that there are points of each color in each row and in any column. Prove that there are two rows and two columns such that their four intersection points are all in different colors.