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Erdős problem 817

Let k≥3k \geq 3. Define gk(n)g_k(n) to be the minimal NN such that {1,...,N}\{1, ..., N\} contains some AA of size ∣A∣=n|A| = n such that ⟨A⟩={∑a∈Aϵaa:ϵa∈{0,1}} \langle A\rangle = \left\{\sum_{a \in A} \epsilon_a a : \epsilon_a \in\{0, 1\}\right\} contains no non-trivial kk-term arithmetic progression. Estimate gk(n)g_k(n). In particular, is it true that g3(n)≫3n g_3(n) \gg 3^n

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FormalConjectures/ErdosProblems/

817.lean

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Let k≥3k \geq 3. Define gk(n)g_k(n) to be the minimal NN such that {1,...,N}\{1, ..., N\} contains some AA of size ∣A∣=n|A| = n such that ⟨A⟩={∑a∈Aϵaa:ϵa∈{0,1}} \langle A\rangle = \left\{\sum_{a \in A} \epsilon_a a : \epsilon_a \in\{0, 1\}\right\} contains no non-trivial kk-term arithmetic progression. Estimate gk(n)g_k(n). In particular, is it true that g3(n)≫3n g_3(n) \gg 3^n

FormalConjectures/ErdosProblems/817.leanErdos817.erdos_8171 lineExact file
True ↔ (fun n => 3 ^ n) =O[Filter.atTop] fun n => ↑(Erdos817.g 3 n)
OpenStatement only, no proof