Formal Verification of the 7-Color Chromatic Number of the Plane via Toroidal Projection and the Irrationality of 2π.
graph-theory formal-verification interactive-theorem-proving irrationality mathlib zulip-bot chromatic-number de-bruijn lean4 2pi formal-proof k-colorability toroidal-topology hadwiger-nelson-problem moser-spindle unit-distance-graph pigeonhole-principle proof-by-exclusion
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Updated
May 14, 2026 - Lean