All open problems
Source labels openChecked July 26, 2026
Erdős Problem 342: Ii
Does Ulam's sequence eventually have periodic differences? That is, is eventually periodic?
Mathematical statement
Does Ulam's sequence eventually have periodic differences? That is, is eventually periodic?
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_342.parts.ii
Complete statement target, proof intentionally absentLean 4
theorem erdos_342.parts.ii : answer(sorry) ↔ ∀ a : ℕ → ℕ, IsUlamSequence a → let d (n : ℕ) : ℤ := a (n + 1) - a n ∃ p > 0, ∀ᶠ m in atTop, d (m + p) = d m := 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