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Erdős problem 402

Prove that, for any finite set A⊂NA\subset\mathbb{N}, there exist a,b∈Aa, b\in A such that gcd⁡(a,b)≤a/∣A∣. \gcd(a, b)\leq a/|A|.

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FormalConjectures/ErdosProblems/

402.lean

Retained formal statement1 of 3

Prove that, for any finite set A⊂NA\subset\mathbb{N}, there exist a,b∈Aa, b\in A such that gcd⁡(a,b)≤a/∣A∣. \gcd(a, b)\leq a/|A|.

FormalConjectures/ErdosProblems/402.leanErdos402.erdos_4021 lineExact file
∀ (A : Finset ℕ), 0 ∉ A → A.Nonempty → ∃ a ∈ A, ∃ b ∈ A, ↑(a.gcd b) ≤ ↑a / ↑A.card
SolvedStatement only, no proof