Nonuniqueness for bounded measurable scalar conductivities in three dimensions

OpenAI

The manuscript constructs two distinct uniformly positive bounded measurable scalar conductivities on the ball B(0,3) in R³. Both equal one near the boundary, differ on a set of positive measure and have the same full weak Dirichlet-to-Neumann operator.

Sources for this record

What was already known

Uniqueness was known for smoother scalar conductivities in dimensions at least three and for bounded measurable scalar conductivities in the plane. Rough anisotropic examples did not give this three-dimensional scalar result.

AI involvement AI-led

OpenAI is credited as author of the model-produced construction. The release identifies no named human checker or explanation of its nested-block mechanism.

The manuscript is institutionally credited to OpenAI and included among model-produced research artifacts.

Importance Major

The counterexample marks a sharp change in the three-dimensional Calderón uniqueness picture at bounded measurable regularity.

Limitations

The Lean target covers the three-dimensional full weak boundary operator. No named human review of its trace-space interpretation was identified; higher dimensions are not claimed.

Technical verification Formal (Lean 4 theorem with Comparator target)

The release reports a Lean proof OAI.ScalarConductivity.main_nonuniqueness; the target statement includes uniform positivity, boundary collar, positive-measure difference, unique weak solutions and the same full boundary operator on the trace quotient.

Formal checking

OAI.ScalarConductivity.main_nonuniqueness in OAI/Analysis/Conductivity/Main.lean against ComparatorChallenges/Conductivity.lean

Checker
Lean 4 development in the OpenAI release
Scope
Two distinct positive bounded measurable scalar conductivities on the three-dimensional ball have the same full weak Dirichlet-to-Neumann operator
Basis
Reported by the linked checker
Evidence source

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

Human understanding Few

No named human explanation of the model's source-annihilation and nested-block mechanism was documented; Few is the evidence default.

Correction and publication history

2026-10-18 · publication

If correct, the counterexample marks a sharp change in the three-dimensional Calderón uniqueness picture at bounded measurable regularity.

Read this published revision