Source labels openChecked July 26, 2026

Erdős Problem 893

Does the limit $\lim_{n\to\infty} \frac{f(2n)}{f(n)}$ tend to infinity?

Combinatorics AMS 5

Mathematical statement

Does the limit $\lim_{n\to\infty} \frac{f(2n)}{f(n)}$ tend to infinity?

(Other finite limits have been ruled out by [KoLu25], see below)

Statement source: Erdős Problems statement material

Statement terms: Source-specific

Source-specific terms. Therefore does not assert reuse rights beyond attributed display.

Statement artifacts, not proofs

These records expose exact Lean propositions and statement-only wrappers. Defining a proposition does not supply a proof of it. A placeholder-bearing target also contains no proof. Elaboration checks syntax and types; it does not certify that a formalization perfectly captures every nuance of the informal problem.

Pinned Lean formulation 1

erdos_893

Canonical source

Complete statement target, proof intentionally absentLean 4

theorem erdos_893 :    answer(sorry) ↔ Tendsto (fun n : ℕ => (f (2 * n) : ℝ) / (f n : ℝ)) atTop atTop := by  sorry

Statement source: Formal Conjectures
Lean version: v4.27.0
Placeholder: Present; no proof artifact
Source evidence: Pinned source index
Fidelity review: Community formulation

References

Pinned Formal Conjectures sourceformalization erdosproblems.com/893background