coloring all postitive integers red or green
Source: Czech-Polish-Slovak Junior Match 2013, Individual p2 CPSJ
March 14, 2020
ColoringcombinatoricsSum
Problem Statement
Each positive integer should be colored red or green in such a way that the following two conditions are met:
- Let be any red number. The sum of any (not necessarily different) red numbers is red.
- Let be any green number. The sum of any (not necessarily different) green numbers is green.
Determine all such colorings.