This theorem could be proved in a new way if Grunb
This theorem could be proved in a new way if Grunbaum's conjecture was proven. Attempts to prove this theorem led to the development of Kempe chains and to snarks, the latter of which is a type of graph. Heinrich Heesch's work on reducibility and discharging was used in the proof by Wolfgang Haken [HAH-ken] and Kenneth Appel, which used a computer to consider 1,936 cases. Name this theorem which, assuming that regions are contiguous, provides a limit to the number of hues needed to fill in a map.
This theorem could be proved in a new way if Grunbaum's conjecture was proven.
four-color map theorem