All open problems
Source labels openChecked July 26, 2026
Erdős Problem 252: K Ge Five
For a fixed k ≥ 5, is ∑ σ k n / n! irrational?.
Mathematical statement
For a fixed k ≥ 5, is ∑ σ k n / n! irrational?.
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_252.variants.k_ge_five
Complete statement target, proof intentionally absentLean 4
theorem erdos_252.variants.k_ge_five : answer(sorry) ↔ ∀ k ≥ 5, Irrational (erdos_252_sum k) := 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