MathDB
Chromatic Number Range

Source: 2011 Philippine Math Olympiad National Stage Problem 5

July 15, 2013
combinatorics unsolvedcombinatoricsChromatic number

Problem Statement

The chromatic number χ\chi of an (infinite) plane is the smallest number of colors with which we can color the points on the plane in such a way that no two points of the same color are one unit apart. Prove that 4≤χ≤74 \leq \chi \leq 7.
Back to ProblemsView on AoPS