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Smale's Mean Value Conjecture


Smale's mean value conjecture (Smale 1981) asserts that, for every complex polynomial p of degree at least 2 and every point z with p^'(z)!=0, some critical point c of p satisfies

 |(p(z)-p(c))/(z-c)|<=|p^'(z)|.

Smale (1981) proved the weaker inequality with right side 4|p^'(z)|. A stronger proposed constant for degree d is (d-1)/d. Unlike the real mean value theorem, the statement compares a secant quotient with a derivative at the prescribed point and selects the other endpoint among the critical points.

Adamczewski (2026) released a proposed counterexample to the constant 1, constructed autonomously by GPT-6 Astra. The claimed polynomial satisfies p(0)=0 and p^'(0)=1, but |p(c)/c|>1 at every critical point. A Lean proof was checked against an independently supplied formal statement with only standard logical axioms. Independent mathematical review of the construction had not been reported as of Sep. 7, 2026 (VibeMathed 2026).


See also

Critical Point, Mean-Value Theorem, Polynomial, Smale's Problems

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References

Adamczewski, T. "Smale's Mean Value Problem." 2026. https://github.com/tadamcz/mean-value-problem.Smale, S. "The Fundamental Theorem of Algebra and Complexity Theory." Bull. Amer. Math. Soc. 4, 1-36, 1981. https://doi.org/10.1090/S0273-0979-1981-14858-8.VibeMathed. "Smale's Mean Value Conjecture." 2026. https://vibemathed.com/problem/smale-s-mean-value-conjecture-k-1.

Cite this as:

Weisstein, Eric W. "Smale's Mean Value Conjecture." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/SmalesMeanValueConjecture.html

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