Erdős ProblemsMathematical logic
Erdős Problem 70
*The relation at **: for finite , where is the first uncountable ordinal.
Mathematical statement
*The relation at **: for finite , where is the first uncountable ordinal.
Note that is not a countable ordinal, so this is not directly an instance of the main Erdős problem (which asks for countable ). Under CH, , making this a self-referential question about .
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
omega_one
theorem omega_one : answer(sorry) ↔ ∀ᵉ (n : ℕ) (_ : 2 ≤ n), OrdinalCardinalRamsey3 (𝔠).ord (Cardinal.aleph 1).ord n := 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