All open problems
Source labels openChecked July 26, 2026

Green's Open ProblemsNumber theory

Ben Green's Open Problem 66

Is there always a sum of two squares between X110X1/4X - \frac{1}{10}X^{1/4} and XX? We formalize this as an eventual statement for sufficiently large real XX.

Mathematical statement

Is there always a sum of two squares between X110X1/4X - \frac{1}{10}X^{1/4} and XX? We formalize this as an eventual statement for sufficiently large real XX.

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_66

Canonical source
Complete statement target, proof intentionally absentLean 4
theorem green_66 :    answer(sorry)       ᶠ X :  in atTop,         n : , IsSumOfTwoSquares n           (n : )  Set.Icc (X - (1 / 10 : ) * X ^ (1 / 4 : )) X := 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