Re:Decades-Old Graph Problem Yields to Amateur Mathematician
by Someone on Wednesday April 18, 2018 @02:28AM
(#16865136)
Be careful in how you phrase that. I would say graph where you say map.
Using map opens you to claims such as that a map containing the North Sea, the kingdom of the Netherlands, the kingdom of Belgium, the French Republic and the Federal Republic of Germany can’t be four-colored because they all border each other (the kingdom of the Netherlands and the French Republic on Saint Martin in the Caribbean)
Historically, other examples likely existed, as land ownership tended to be patchy in feudal Europe, and, later, colonies added borders between various European countries.
Using map opens you to claims such as that a map containing the North Sea, the kingdom of the Netherlands, the kingdom of Belgium, the French Republic and the Federal Republic of Germany can’t be four-colored because they all border each other (the kingdom of the Netherlands and the French Republic on Saint Martin in the Caribbean)
Historically, other examples likely existed, as land ownership tended to be patchy in feudal Europe, and, later, colonies added borders between various European countries.