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Erdős problem 41

Let A ⊆ ℕ be an infinite set such that the triple sums a + b + c are all distinct for a, b, c in A (aside from the trivial coincidences). Is it true that liminf n → ∞ |A ∩ {1, …, N}| / N^(1/3) = 0?

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FormalConjectures/ErdosProblems/

41.lean

Retained formal statement1 of 2

Let A ⊆ ℕ be an infinite set such that the triple sums a + b + c are all distinct for a, b, c in A (aside from the trivial coincidences). Is it true that liminf n → ∞ |A ∩ {1, …, N}| / N^(1/3) = 0?

FormalConjectures/ErdosProblems/41.leanErdos41.erdos_413 linesExact file
∀ (A : Set ℕ),  Erdos41.NtupleCondition A 3 →    A.Infinite → Filter.liminf (fun N => ↑(A ∩ Set.Icc 1 N).ncard / ↑N ^ (1 / 3)) Filter.atTop = 0
OpenStatement only, no proof