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Erdős problem 280

Let n1<n2<⋯n_1<n_2<\cdots be an infinite sequence of integers with associated ak(modnk)a_k\pmod{n_k}, such that for some ϵ>0\epsilon>0 we have nk>(1+ϵ)klog⁡kn_k>(1+\epsilon)k\log k for all kk. Then #{m<nk:m≢ai(modni) for 1≤i≤k}≠o(k). \#\{ m<n_k : m\not\equiv a_i\pmod{n_i} \textrm{ for }1\leq i\leq k\}\neq o(k).

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The source's own material, retained exactly.

1 retained statement36c6d0fef71a

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FormalConjectures/ErdosProblems/

280.lean

Retained formal statement1 of 1

Let n1<n2<⋯n_1<n_2<\cdots be an infinite sequence of integers with associated ak(modnk)a_k\pmod{n_k}, such that for some ϵ>0\epsilon>0 we have nk>(1+ϵ)klog⁡kn_k>(1+\epsilon)k\log k for all kk. Then #{m<nk:m≢ai(modni) for 1≤i≤k}≠o(k). \#\{ m<n_k : m\not\equiv a_i\pmod{n_i} \textrm{ for }1\leq i\leq k\}\neq o(k).

Cambie observed that this is false.

FormalConjectures/ErdosProblems/280.leanErdos280.erdos_2806 linesExact file
False ↔  ∀ (n a : ℕ → ℕ),    StrictMono n →      (∀ (i : ℕ), 1 ≤ i → a i < n i) →        (∃ ε, 0 < ε ∧ ∀ (k : ℕ), 1 ≤ k → ↑(n k) > (1 + ε) * ↑k * Real.log ↑k) →          ¬Filter.Tendsto (fun k => ↑(Erdos280.uncoveredCount n a k) / ↑k) Filter.atTop (nhds 0)
SolvedProof has a holelean4external proof

The proof uses `sorry`: part of the argument is written but not proved. Lean accepts the file; it does not accept the theorem.