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Four color theorem
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==Use outside of mathematics== Despite the motivation from [[map coloring|coloring political maps of countries]], the theorem is not of particular interest to [[cartographers]]. According to an article by the math historian [[Kenneth May]], "Maps utilizing only four colors are rare, and those that do usually require only three. Books on cartography and the history of mapmaking do not mention the four-color property".{{sfnp|Wilson|2014|loc=2}} The theorem also does not guarantee the usual cartographic requirement that non-contiguous regions of the same country (such as the exclave [[Alaska]] and the rest of the [[United States]]) be colored identically. Because the four-color theorem does not apply when the regions on the map are not contiguous, it also does not apply to the world map. On the world map, the ocean, Belgium, Germany, the Netherlands, and France all border each other because the Netherlands borders France on the island of [[Saint Martin (island)|Saint Martin]]. This is the only counterexample.{{Citation needed|date=November 2024}}
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