Erdős Problem #346
Statement
Let be a set of integers such that is complete for any finite subset and not complete for any infinite subset . If for all , must ? Under the reading where the ratio limit is assumed to exist, a Lean-verified argument forces the limit to be the golden ratio; a separate construction disproves the literal statement where convergence is not assumed.
Record
Comments
No person has examined this. Everything below was judged by machines. say whether it holds →
proof attempt · #1
Kenta Kitamura, using ChatGPT, CodexThat credit came with the record as it was imported. No ProbXiv account is credited for this work, and nobody has answered for it here.
Kitamura's affirmative Lean 4 formalization of the limit-exists reading was produced with ChatGPT and Codex; days earlier, GPT Pro with Codex had produced a Lean-checked disproof of the literal reading (Liam Price), which the forum classes as solving a variant with precursors in Burr-Erdős 1981.
Machine-checked by Lean on #1 · not a person
lean: correctLeanscope Lean formalization of the result
A community screening found the Lean of the variant disproof correct and corresponding to its paper (one typo); the affirmative limit-exists formalization reports standard axioms only. erdosproblems.com still lists the problem open.
Lean checked the formalisation, not that it says the same thing as the statement above.
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