Resolving Thinness of Degree-Six Symplectic Hypergeometric Monodromy Groups

J. Maxwell Riestenberg, Diaaeldin Taha, Steve Trettel, Anna Wienhard

AlphaEvolve found explicit witness words that Riestenberg, Taha, Trettel and Wienhard use to prove that the degree-six symplectic hypergeometric monodromy groups C-47 and C-55 have finite index in their ambient integral symplectic groups and are arithmetic.

Sources for this record

What was already known

Bajpai, Dona and Nitsche listed C-32, C-47 and C-55 as unresolved. An existing arithmeticity criterion reduced the latter two cases to suitable commuting-transvection witnesses.

AI involvement AI-centered

AlphaEvolve generated the retained witness words. The human authors applied the existing criterion, checked the words with exact rational arithmetic and wrote the mathematical proof.

AlphaEvolve generated the retained witness words needed for the arithmeticity argument; humans selected the criterion, checked the certificates and wrote the proof.

Importance Notable

The two certificates settle C-47 and C-55 and complete their arithmetic classification alongside a separate C-32 result.

Limitations

The C-32 thinness proof uses a different ChatGPT-found cone and is outside this contribution. The exact matrix checks are source-reported.

Technical verification Formal (exact rational matrix arithmetic + human)

Theorem 1's explicit words are checked by exact rational matrix arithmetic for rank-one unipotence, commuting and symplectic orthogonality, then the authors apply the cited arithmeticity criterion. The source reports both exact computer checks and independent human mathematical verification; neither was reproduced here.

Formal checking

Deterministic exact matrix arithmetic over Q on the published witness words

Checker
Authors' exact-arithmetic computation
Scope
C-47 and C-55 witness words satisfy the transvection conditions used in Theorem 1
Basis
Reported by the linked checker

Independent mathematical argument and certificate verification written by the authors

Checker
Riestenberg, Taha, Trettel and Wienhard
Scope
The AlphaEvolve certificates prove arithmeticity of C-47 and C-55 under the stated criterion
Basis
Reported by the linked checker
Evidence source

Checking a formal statement does not establish that it matches the original problem.

Human understanding Full

The authors explain how each witness word yields commuting, independent, symplectically orthogonal transvections and why the prior criterion gives finite index.

Correction and publication history

2026-10-18 · publication

The two certificates settle C-47 and C-55 and complete their arithmetic classification alongside a separate C-32 result.

Read this published revision