All open problems
Source labels openChecked July 26, 2026

Green's Open ProblemsCombinatorics

Ben Green's Open Problem 58

Suppose A,B{1,,N}A, B ⊆ \{1, \dots, N\} both have size at least N0.49N^{0.49}. Must the sumset A+BA + B contain a composite number?

Mathematical statement

Suppose A,B{1,,N}A, B ⊆ \{1, \dots, N\} both have size at least N0.49N^{0.49}. Must the sumset A+BA + B contain a composite number?

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_58

Canonical source
Complete statement target, proof intentionally absentLean 4
theorem green_58 :    answer(sorry)       ᶠ (N : ) in Filter.atTop, ᵉ (A  Finset.Icc 1 N) (B  Finset.Icc 1 N),        (N : ) ^ (0.49 : )  (A.card : )         (N : ) ^ (0.49 : )  (B.card : )          m  (A + B), m.Composite := 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