Four-color matching

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Four-color matching is a concept in graph theory that asks whether any map drawn on a plane can be colored using at most four colors in such a way that no two adjacent regions are of the same color. This problem was first posed in 1852 by Francis Guthrie, and it was proven in 1976 by Kenneth Appel and Wolfgang Haken using a computer-assisted proof. The theorem is fundamental in graph theory and has implications in various fields such as cartography and computer science.