The Four-Color Theorem 1852–1976
Summary
This article provides a historical overview of the four-color theorem, tracing the progression from early hypotheses to a computer-assisted proof. It highlights key figures (Guthrie, De Morgan, Kempe, Heesch, Appel and Haken) and concepts (reducible configurations, Kempe chains, discharging) and shows how computational methods evolved to formal verification.