Polynomial evaluation in just two multiplications: 100-page proof finally verified in Lean by AI

srchvrs · x · 2026-09-11

A fun result shared in reply: a quartic polynomial P(x) can be evaluated with just two(!) multiplications using a nested form y = (x + b₀)x + b₁. The authors proved it years ago but the 100-page proof made them unsure enough to publish — until AI verified it in Lean.

Notably, the original result was "done entirely without AI"; AI only served as the verifier.

Related event: Century-old-style proof verified in Lean lets quartic polynomials be evaluated with just two multiplications(5 posts)→

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