All open problems
Source labels openChecked July 26, 2026
Busy Beaver
Determine the value of the Busy Beaver function at n = 6.
Mathematical statement
Determine the value of the Busy Beaver function at n = 6.
Statement source: Wikipedia 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
BB_6
Complete statement target, proof intentionally absentLean 4
theorem BB_6 : BB 6 = answer(sorry) := 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