Theorem · version 2

An analytic tenfold counterexample

Statement

There exist a bounded simply connected non-disk Ω with real-analytic Jordan boundary and tenfold symmetry, a nonconstant classical real u and k∈(31.967007261,31.967007293)k\in(31.967007261,31.967007293) such that Δu+k2u=0\Delta u+k^2u=0 in Ω, u = 1 and ∂νu=0\partial_\nu u=0 on ∂Ω.

Assumptions

  • Planar domain; real-analytic boundary.
  • The exact construction and certified bounds of Colbrook–Stepaniants.

Scope

The narrow k interval belongs to the numerical certificate. The corresponding eigenvalue is k², not k.

Geometry
Simply connected non-disk; tenfold symmetry
Boundary / field
Real-analytic Jordan boundary; classical real field
Numerical input
k ∈ (31.967007261,31.967007293); eigenvalue λ = k²
Evidence scope
Numerical certificate and separately linked complete formal proof; the latter uses coarser exact bounds at the same dyadic centre

Evidence

Source reports

Formal proofs

Connections

In this problem · publication v6 · Selected context

Schiffer and Pompeiu conjectures →

Counterexample · Proved

Relationship not independently reviewed. This concerns its use in this problem.

Sources

A computer-assisted counterexample to the planar Pompeiu and Schiffer conjectures →

Matthew J. Colbrook · George Stepaniants · Preprint · Publication date Aug 3, 2026

Revision & attribution

Source revision: 2026-08-03. Observed Oct 13, 2026.

The paper credits GPT-5.5 Codex for debugging early computational code, checked line by line by the authors. The authors own the mathematical argument and certificate.

Lean proof of the analytic tenfold construction →

Matthew J. Colbrook · George Stepaniants · Project documentation

Public formal source; execution and statement correspondence are separate checks.

Revision & attribution

Source revision: 2fb3f2ecafd3233dbca390d73e764fe6e04a9c7d. Observed Oct 13, 2026.

No specific AI contribution is attributed by this source record.

Lean proof of the analytic tenfold construction — pinned source: 2fb3f2ecafd3233dbca390d73e764fe6e04a9c7d.

Numerical certificate and reproduction report →

Matthew J. Colbrook · George Stepaniants · Project documentation

Revision & attribution

Source revision: 2fb3f2ecafd3233dbca390d73e764fe6e04a9c7d. Observed Oct 13, 2026.

No specific AI contribution is attributed by this source record.

Frozen numerical certificate archive: 2fb3f2ecafd3233dbca390d73e764fe6e04a9c7d. Source reports rigorous interval and exact rational verification. OpenMath has not run the certificate or reproduced its numerical audits.

History

Statement versions

Statement versions and problem publication versions are separate. A new publication can update context or sources while retaining the same statement.

Assessment history · 2

Assessments retained in these publication records. Earlier statement versions retain their own source histories.

Record details
Claim ID
claim-schiffer-analytic-tenfold-witness
Statement version
2
SHA-256
2b48ed0b43ddba91e6a9ecb85361b8ba71104fdffec887610cbe1f3fcc94b3ab

Publication records