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import FormalConjecturesUtilErdős Problem 312
namespace Erdos312
Does there exist a constant c > 0 such that, for any K > 1, whenever A is a sufficiently large
finite multiset of integers with $\sum_{n \in A} 1/n > K$ there exists some $S \subseteq A$ such that
$1 - \exp(-(c*K)) < \sum_{n \in S} 1/n \le 1$?
@[category research open, AMS 5 11]
theorem erdos_312 :
answer(sorry) ↔
∃ (c : ℝ), 0 < c ∧
∀ (K : ℝ), 1 < K →
∃ (N₀ : ℕ),
∀ (n : ℕ) (a : Fin n → ℕ),
(n ≥ N₀ ∧ (∑ i : Fin n, (a i : ℝ)⁻¹) > K) →
∃ (S : Finset (Fin n)),
1 - Real.exp (-(c * K)) < (∑ i ∈ S, (a i : ℝ)⁻¹) ∧
∑ i ∈ S, (a i : ℝ)⁻¹ ≤ 1 := ⊢ True ↔
∃ c,
0 < c ∧
∀ (K : ℝ),
1 < K →
∃ N₀,
∀ (n : ℕ) (a : Fin n → ℕ),
n ≥ N₀ ∧ ∑ i, (↑(a i))⁻¹ > K →
∃ S, 1 - Real.exp (-(c * K)) < ∑ i ∈ S, (↑(a i))⁻¹ ∧ ∑ i ∈ S, (↑(a i))⁻¹ ≤ 1
All goals completed! 🐙
end Erdos312