The four-color theorem: the Appel–Haken computer-assisted proof

What changed

Every planar map can be colored with at most four colors so adjacent regions have different colors.

Scientific scope

Every planar map can be colored with at most four colors so adjacent regions have different colors. Scope limitation: Computer-assisted proof is distinct from modern generative AI. Later corrections and formalizations belong in separate entries.

Evidence

Assessment uses the catalogue-linked source evidence for the stated contribution. Computer-assisted proof is distinct from modern generative AI. Later corrections and formalizations belong in separate entries.

Contributors

• Kenneth Appel · SCIENCE: Named source contributor; exact labor shares are not measured.
• Wolfgang Haken · SCIENCE: Named source contributor; exact labor shares are not measured.

• Appel and Haken, Every planar map is four colorable (1976)

Provisional WRS assessment, edition 2026-10-16.1. Independent expert calibration is pending. This grade does not certify correctness or assign ownership.

Full scientific record · Browse contribution grades · Request a correction