Erdős ProblemsMathematical logic
Erdős Problem 70
First open case beyond Erdős–Rado*: .
Mathematical statement
First open case beyond Erdős–Rado*: .
Erdős and Rado proved for every finite
(see erdos_rado), which covers all red ordinals below .
This variant asks whether the result extends to , the simplest
countable ordinal not covered by their theorem.
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_times_two_four
theorem omega_times_two_four : answer(sorry) ↔ OrdinalCardinalRamsey3 (𝔠).ord (ω * 2) 4 := 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