MathDB
Colored triangles with disjoint interiors

Source: Miklós Schweitzer 2014, P3

December 23, 2014
combinatorial geometrycombinatorics proposedcombinatorics

Problem Statement

We have 4n+54n + 5 points on the plane, no three of them are collinear. The points are colored with two colors. Prove that from the points we can form nn empty triangles (they have no colored points in their interiors) with pairwise disjoint interiors, such that all points occurring as vertices of the nn triangles have the same color.