Explore one of mathematics' most celebrated theorems through 21 interactive demonstrations.
What is the four color conjecture and why does it matter?
Dual graphs, planar graphs, and the graph theory reformulation
V - E + F = 2, Kuratowski's theorem, and why planarity matters
Kempe's proof attempt, Heawood's correction, and the five color theorem
The two pillars of the proof: reducible configurations and the discharging method
Appel-Haken 1976, the proof controversy, and modern verification
Chromatic polynomials, list coloring, and beyond four colors