AMR-022-6050 · Complete counterexample

A Counterexample to the Area Inequality for Geometric Means of Exterior Univalent Functions

Manuscript 25 October 2026 · Online 25 October 2026

math.CVUnrefereed preprint

Abstract

A question of D. K. Thomas, recorded as Problem 6.50 in Hayman and Lingham's Research Problems in Function Theory, asks whether geometric means of normalized exterior univalent functions satisfy the area-theorem coefficient inequality. We give an explicit counterexample at exponent 1/2. The two factors are odd, zero-free and univalent on |z|>1, and their normalized geometric mean is analytic throughout that domain. Its first four nonzero negative Laurent coefficients have weighted squared sum 269463/262144>1. A fixed radial dilation by 1001/1000 gives factors and a mean analytic across the unit circle, with full coefficient sum finite and greater than 101/100. The proof uses elementary conformal maps and exact rational arithmetic. This gives a negative answer to the entire single-question frozen UnsolvedMath record AMR-022-6050. The package includes the complete four-page proof, exact and symbolic checks, and a source/scope audit. AI-assisted self-audited preprint; no independent peer review, formal verification or absolute-priority certification is claimed.

Record

Affiliation
Mercury Software GmbH
Result
Complete counterexample
Categories
math.CV
Manuscript
25 October 2026
Online release
25 October 2026
Version
1.0
License
Creative Commons Attribution 4.0 International

Files and verification

The PDF is the canonical reading copy. The source archive contains the LaTeX manuscript, bibliography, reproducibility material, and audit documents without build artefacts.

Citation

Alper Ferudun, “A Counterexample to the Area Inequality for Geometric Means of Exterior Univalent Functions,” EulerSolve Research Papers, AMR-022-6050, 2026. https://doi.org/10.5281/zenodo.23649631.

BibTeX
@misc{ferudun2026geometricarea,
  author = {Ferudun, Alper},
  title = {A Counterexample to the Area Inequality for Geometric Means of Exterior Univalent Functions},
  year = {2026},
  howpublished = {EulerSolve Research Papers},
  url = {https://eulersolve.org/papers/amr-022-6050/},
  doi = {10.5281/zenodo.23649631},
  note = {AMR-022-6050; unrefereed preprint}
}

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