50 points in plane
Source: JBMO 2007, Bulgaria, problem 3
June 28, 2007
combinatorics proposedcombinatoricscombinatorial geometryHi
Problem Statement
Given are points in the plane, no three of them belonging to a same line. Each of these points is colored using one of four given colors. Prove that there is a color and at least scalene triangles with vertices of that color.