Almost-Orthogonality in Lp Spaces: A Case Study with Grok

Ziang Chen, Jaume de Dios Pont, Paata Ivanisvili, Jose Madrid, Haozhu Wang

For p>2, a common-set/private-set construction shows Carbery’s proposed exponent c=2 fails. Grok also supplied the kernel inequality used to establish the optimal necessary constraint c≤p′.

Sources for this record

What was already known

Carbery had proposed the c=2 sharpened Lp triangle inequality. The human authors already suspected a counterexample and had found one by random brute-force search, but it gave neither a structural explanation nor the optimal exponent p′.

AI involvement AI-centered

Grok supplied the structural counterexample and the proof of the key kernel lemma. Chen, de Dios Pont, Ivanisvili, Madrid and Wang corrected and generalized the example, checked the lemma and completed the argument.

Grok originated the retained structural counterexample and the key optimality lemma, while the authors supplied the reduction, corrections and broader paper.

Importance Notable

Refutes the proposed exponent and identifies the sharp necessary exponent constraint.

Limitations

The original model example had numerical errors, corrected by the authors. Their separate three-function inequality and root-counting proof are human-led results.

Technical verification Formal (human)

The authors explicitly report verifying the correctness of Grok's Lemma 2.3 proof and carefully checking the details of its use. They present a corrected counterexample with a direct limiting calculation. The check is source-reported human proof review, not independently reproduced.

Formal checking

The authors explicitly report verifying the correctness of Grok's Lemma 2.3 proof and carefully checking the details of its use. They present a corrected counterexample with a direct limiting calculation. The check is source-reported human proof review, not independently reproduced.

Checker
Chen, de Dios Pont, Ivanisvili, Madrid and Wang, the human paper authors
Scope
Grok's Lemma 2.3 and its use in the optimal exponent argument
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 the shared set plus private sets and the limiting calculation that forces c≤p′; they also explain how the Grok lemma enters their reduction.

Correction and publication history

2026-10-18 · publication

Grok supplied the structural counterexample and key lemma; the authors corrected, checked and explained them.

Read this published revision