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Source labels openChecked July 26, 2026

Erdős ProblemsNumber theory

Erdős Problem 142: Lower

Show that rk(N)=ok(N/logN)r_k(N) = o_k(N / \log N), where rk(N)r_k(N) the largest possible size of a subset of {1,,N}\{1, \dots, N\} that does not contain any non-trivial kk-term arithmetic progression.

Mathematical statement

Show that rk(N)=ok(N/logN)r_k(N) = o_k(N / \log N), where rk(N)r_k(N) the largest possible size of a subset of {1,,N}\{1, \dots, N\} that does not contain any non-trivial kk-term arithmetic progression.

Statement source: Erdős 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

erdos_142.variants.lower

Canonical source
Complete statement target, proof intentionally absentLean 4
theorem erdos_142.variants.lower (k : ) (hk : 1 < k) :    (fun N => (r k N : )) =o[atTop] (fun N :  => N / (N : ).log) := 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