All open problems
Source labels openChecked July 26, 2026

Green's Open ProblemsNumber theory

Green's Open Problem 44

Sieve [N][N] by removing half the residue classes mod pip_i, for primes 2p1<p2<<p1000<N9/102 \leqslant p_1 < p_2 < \dots < p_{1000} < N^{9/10}. Does the remaining set have size at most 110N\frac{1}{10} N?

Mathematical statement

Sieve [N][N] by removing half the residue classes mod pip_i, for primes 2p1<p2<<p1000<N9/102 \leqslant p_1 < p_2 < \dots < p_{1000} < N^{9/10}. Does the remaining set have size at most 110N\frac{1}{10} N?

We interpret "half the residue classes" as pi/2\lfloor p_i / 2 \rfloor.

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_44

Canonical source
Complete statement target, proof intentionally absentLean 4
theorem green_44 :    answer(sorry)   (N : ) (p : Fin 1000  ) (A : (i : Fin 1000)  Finset (ZMod (p i))),      let remaining := (Finset.Icc 1 N).filter (fun x =>  i, (x : ZMod (p i))  A i)      ( i, (p i).Prime)       StrictMono p       (p 999) ^ 10 < N ^ 9       ( i, (A i).card = (p i) / 2)       10 * remaining.card  N := 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