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Erdős problem 329

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Erdős Problem 329. Let A ⊆ ℕ be a Sidon set. How large can lim sup_{N → ∞} |A ∩ {1,…,N}| / N^{1/2} be?

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FormalConjectures/ErdosProblems/

329.lean

Retained formal statement4 of 6

Erdős proved that upper density 1 / 2 can be attained; in particular, there exists a Sidon set whose upper density is *at least* 1 / 2.

FormalConjectures/ErdosProblems/329.leanErdos329.erdos_329.variants.lower_bound1 lineExact file
∃ A, IsSidon A ∧ Erdos329.sidonUpperDensity A ≥ 1 / 2
SolvedStatement only, no proof