Erdős problem 510

Chowla's cosine problem

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The source's own material, retained exactly.

3 retained statements36c6d0fef71a

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FormalConjectures/ErdosProblems/

510.lean

Retained formal statement3 of 3

Ruzsa [Ru04] proved an upper bound of $-\exp(O(\sqrt{\log N})$ .

FormalConjectures/ErdosProblems/510.leanErdos510.erdos_510.variants.ruzsa4 linesExact file

1∃ c,2  ∃ (_ : 0 < c),3    ∀ᶠ (N : ℕ) in Filter.atTop,4      ∀ (A : Finset ℕ), 0 ∉ A → A.card = N → ∃ θ, ∑ n ∈ A, Real.cos (↑n * θ) < -Real.exp (c * √(Real.log ↑N))

SolvedStatement only, no proof