All open problems
Source labels openChecked July 26, 2026

Green's Open ProblemsCombinatorics

Ben Green's Open Problem 5: Sl Two

A good model problem would be to determine the largest product-free subsets of SL2(Fp)\mathrm{SL}_2(\mathbb{F}_p).

Mathematical statement

A good model problem would be to determine the largest product-free subsets of SL2(Fp)\mathrm{SL}_2(\mathbb{F}_p).

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_5.variants.sl_two

Canonical source
Complete statement target, proof intentionally absentLean 4
theorem green_5.variants.sl_two (p : ) [Fact p.Prime] :    let S : Finset (SL₂ p) := answer(sorry)    MaximalFor (IsProductFree (M := SL₂ p)) Set.ncard (S : Set (SL₂ p)) := 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