Other · Sep 16, 2026
Four Color Theorem formalized in Lean 4 by AI agents, in two independent developments
GitHub: corun1024/4ct, Chris Emery's Lean 4 proof
Contributors
Claude Fable 5.1 · Claude Opus 5 · Claude Opus 5.5 · Chris Emery · Robert D. Barish
AI systems: Claude Fable 5.1, Claude Opus 5, Claude Opus 5.5