Limits RegistryPUBLIC RECORD
Limits RegistryKenneth Appel and Wolfgang Haken proved the Four Color Theorem in 1976 at the University of Illinois, reducing the problem to checking 1,936 (later reduced) unavoidable configurations by computer — the first widely accepted major mathematical theorem whose proof depended essentially on computer verification, which was controversial among mathematicians at the time. A cleaner, independently verified proof was published by Robertson, Sanders, Seymour, and Thomas in 1997.
The question, scope, and sources behind this Registry record.
Kenneth Appel and Wolfgang Haken proved the Four Color Theorem in 1976 at the University of Illinois, reducing the problem to checking 1,936 (later reduced) unavoidable configurations by computer — the first widely accepted major mathematical theorem whose proof depended essentially on computer verification, which was controversial among mathematicians at the time. A cleaner, independently verified proof was published by Robertson, Sanders, Seymour, and Thomas in 1997.
Any planar map can be colored using at most four colors such that no two adjacent regions share the same color.
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Current frontiers derived from accepted Claims.
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The frontier is not sacred
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The frontier as it changed over time.
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1 accepted Claim, with 1 linked evidence records.
Permanent ID limitsregistry.com/limits/LR-FOUR-COLOR-THEOREM
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Limits Registry. LR-FOUR-COLOR-THEOREM. Proof of the Four Color Theorem. 2026.