Four-Color Maps
Wolfram Demonstrations Project · 2008
For 66 years research on the fourcolor theorem was dominated by Taits Hamiltonian graph conjecture any cubic polyhedral graph has a Hamiltonian cycle In a graph cubic means that every vertex is incident with exactly three edges Any planar graph can be made cubic by drawing a small circle around any vertex with valence greater than three and eliminating the original vertex Tutte in 1946 found the f