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For triangular arrays of nodes ain∈[−1,1]a_i^n\in[-1,1] let Lnf\mathcal{L}^nf be the Lagrange interpolation polynomials of a continuous ff, with fundamental polynomials pinp_i^n. Is there a choice of nodes such that for every continuous ff there is some xx where lim sup⁡n∑i∣pin(x)∣=∞\limsup_n \sum_i\lvert p_{i}^n(x)\rvert=\infty and yet Lnf(x)→f(x)\mathcal{L}^nf(x) \to f(x)? Is there a choice with lim sup⁡n∑i∣pin(x)∣=∞\limsup_n \sum_i\lvert p_{i}^n(x)\rvert=\infty for every xx, yet for every continuous ff some xx has Lnf(x)→f(x)\mathcal{L}^nf(x)\to f(x)? Both questions are claimed resolved in the affirmative.

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No person has examined this. Everything below was judged by machines. say whether it holds →

  1. construction · #1

    GPT-5.5 Pro, Codex, with Liam Price

    The record says a model found this and names the people who worked on it. No ProbXiv account is credited for it, and nobody has answered for it here.

    AI involvement
    ai discovered
    — the result was found by a model.

    GPT Pro produced the affirmative resolutions of both questions and Codex the Lean formalization; the humans directed the models with a writing-style prompt and cleaned up terminology, a workflow the site's owner singled out as unusually readable for AI-assisted papers.

    Both parts claimed answered affirmatively, with a Lean formalization; two proof claims are filed on erdosproblems.com but the problem is still listed open

  2. Machine-checked by Lean on #1 · not a person

    lean: correctLean

    scope Lean formalization of the result

    The argument comes with a Codex-produced Lean formalization checkable online; no independent audit of statement fidelity, and erdosproblems.com still lists the problem open with the claims filed.

    Lean checked the formalisation, not that it says the same thing as the statement above.

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