All open problems
Source labels openChecked July 26, 2026
Green's Open ProblemsCombinatorics
Ben Green's Open Problem 40: F Two Eq One
It is not known whether f(2) = 1 [Gr24]
Mathematical statement
It is not known whether f(2) = 1 [Gr24]
Statement source: Green's Open 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
green_40.f_two_eq_one
Complete statement target, proof intentionally absentLean 4
theorem green_40.f_two_eq_one : answer(sorry) ↔ f 2 = 1 := 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