The Radchenko–Viazovska question on Fourier interpolation
resolvedconfidence 70%
VibeMathed reports this item as resolved. VibeMath preserves that report as a source assertion and has not independently authored a plain-language mathematical explanation.
Precise statement
For every $0\le \beta\le 1/2$, we construct a nonzero real-valued continuous function $f_\beta$ in $L^1(\mathbb R)\cap L^2(\mathbb R)$ such that $\widehat f_\beta=f_\beta$ and
$$
f_\beta\!\left(\frac{\sqrt n}{[\log(e+n)]^\beta}\right)=0
$$
for all $n\ge0$. The case $\beta=0$ settles in the negative a question raised by Radchenko and Viazovska regarding their Fourier interpolation formula.
The source statement is reproduced for indexing with attribution. Mathematical correctness requires domain-expert or mechanical review. VibeMath has not independently audited statement
fidelity, correctness, priority, or novelty.
What AI did
ChatGPT (OpenAI, model version unstated)
The authors state that OpenAI's ChatGPT provided exploratory input and calculations that were essential in the development of the paper. The disclosure does not identify a specific model version or isolate which theorem, lemma, or proof step originated from ChatGPT, so the safest attribution is substantive AI-assisted discovery rather than AI-discovered.
Unreviewed. arXiv 2608.13468 read here; the acknowledgement thanks ChatGPT, "whose exploratory input and calculations were essential in the development of this paper", naming no model version and isolating no step. A complete conventional proof by the authors; not refereed; no formalization.
For every $0\le \beta\le \tfrac12$, Bondarenko and Seip construct a nonzero real-valued continuous even function
$$
f_\beta\in L^1(\mathbb R)\cap L^2(\mathbb R)
$$
such that
$$
\widehat f_\beta=f_\beta
$$
and
$$
f_\beta\!\left(\frac{\sqrt n}{[\log(e+n)]^\beta}\right)=0
\qquad(n\ge0).
$$
They normalize the construction by requiring $f_\beta(1/2)=1$, so the function is genuinely nontrivial.
For $\beta=0$, this gives a nonzero Fourier-invariant function vanishing at every $\sqrt n$, which answers the question negatively: their interpolation formula for even Schwartz functions does not extend merely under the assumption that the interpolation series is well-defined and absolutely convergent.
More strongly, for every $0<\beta\le1/2$ the zero set can be logarithmically denser than the square-root sequence. These sampling points, together with $1/2$, form a universal interpolating sequence for a suitable reproducing-kernel Hilbert space of Fourier-invariant Hermite expansions.
Known method families
argument (source-reported)
Source-reported tools: argument.
Independent: unknown · difference confidence: 0
What remains uncertain
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VibeMath has not independently audited the mathematical statement, proof, or novelty claim.