IMO ShortList 1999, combinatorics problem 6
Source: IMO ShortList 1999, combinatorics problem 6
November 14, 2004
functionlinear algebracombinatoricsIMO ShortlistRamsey Theory
Problem Statement
Suppose that every integer has been given one of the colours red, blue, green or yellow. Let and be odd integers so that . Show that there are two integers of the same colour whose difference has one of the following values: or .