Four Color Theorem (1976)
Kenneth Appel and Wolfgang Haken proved the four color theorem using 1,936 computer-checked cases. No human could verify the computer's work by hand, and mathematicians split over whether it counted as a proof.
Many mathematicians refused to accept the result for years; simpler proofs were sought.
The theorem was accepted, and machine-checked proof became a standard, legitimate tool in mathematics.
The current AI-math dispute echoes the four color controversy: proofs that no person can fully trace face skepticism before eventual acceptance — or rejection.
