A sharp Fourier certificate for planar circle packing

OpenAI

A real radial Schwartz function on the plane has nonnegative Fourier transform, is nonpositive beyond unit distance, and has normalized origin values making the Cohn–Elkies linear-programming bound attain the triangular-packing density π/(2√3).

Sources for this record

What was already known

Thue’s theorem already established the optimal planar packing density. Cohn and Elkies conjectured that their Fourier bound attains it exactly; numerical approximations had not proved sharpness.

AI involvement AI-led

OpenAI is credited as author of the internally produced mathematical manuscript; individual-session autonomy is undocumented.

Institutional AI authorship and collection provenance support AI-led production.

Importance Notable

Claims an exact sharp certificate for the planar Fourier packing bound.

Limitations

This certificate does not prove uniqueness of periodic equality cases or the stronger prescribed-zero condition. A possibly related 2026 thesis claim has not been fully compared.

Technical verification Formal (Lean 4; exact interval computation with python-flint)

The repository reports a Lean proof of the exact normalized Fourier-certificate existence theorem. Its separate finite interval verifier checks only matrix, residual, Bernstein, and scalar comparisons; analytic parts are covered by the Lean theorem rather than that script alone.

Formal checking

Existence of a radial Schwartz function meeting the sharp planar Fourier certificate conditions. formal proof

Checker
Lean kernel via OAI.sharp_fourier_certificate
Scope
Existence of a radial Schwartz function meeting the sharp planar Fourier certificate conditions
Basis
Reported by the linked checker
Evidence source

Formal checking

Finite matrix, residual, Bernstein, and scalar comparisons used in the certificate. exact interval arithmetic

Checker
Project verify_all.py using python-flint
Scope
Finite matrix, residual, Bernstein, and scalar comparisons used in the certificate
Basis
Reported by the linked checker
Evidence source

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

Human understanding Few

Default: the model-authored exposition does not establish a named human understanding of the certificate's construction.

Correction and publication history