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Problem packetResearch packetR1206

R1206Sourced evidence

Current status and unresolved remainder

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Authored summary

OPEN as of 2026-07-31. The maintained Erdős Problems database at commit 8138974387d9030542daabe67faaa33eff9356f8 lists Problem 142 as open. The unresolved remainder is the full displayed statement. Give a rigorous proof or counterexample that completely resolves this statement: Erdős Problem 142: For a positive integer \(N\), let \(r_3(N)\) denote the largest possible cardinality of a subset of \(\{1, 2, \dots, N\}\) that contains no non-trivial 3-term arithmetic progression. A 3-term arithmetic progression is called non-trivial if its terms are distinct. Determine whether there exists a function \(f: \mathbb{N} \to \mathbb{R}\) such that \(r_3(N) = \Theta(f(N))\) as \(N \to \infty\), and if so, identify such a function. That is, find an explicit asymptotic formula for \(r_3(N)\) up to constant factors.

The record cites sources for its explanation.

Recorded status: reported

Recorded scope: No scope is recorded.

Originating problem: Asymptotic formula for the maximum size of a 3-term-AP-free subset of \(\{1,\dots,N\}\)

Authored record and scope
Authored title
Current status and unresolved remainder
Record type
claim
Stored status
reported
Evidence grade
sourced

2Authored explanation

OPEN as of 2026-07-31. The maintained Erdős Problems database at commit 8138974387d9030542daabe67faaa33eff9356f8 lists Problem 142 as open. The unresolved remainder is the full displayed statement.

A complete resolution must satisfy this condition: Give a rigorous proof or counterexample that completely resolves this statement: Erdős Problem 142: For a positive integer \(N\), let \(r_3(N)\) denote the largest possible cardinality of a subset of \(\{1, 2, \dots, N\}\) that contains no non-trivial 3-term arithmetic progression. A 3-term arithmetic progression is called non-trivial if its terms are distinct. Determine whether there exists a function \(f: \mathbb{N} \to \mathbb{R}\) such that \(r_3(N) = \Theta(f(N))\) as \(N \to \infty\), and if so, identify such a function. That is, find an explicit asymptotic formula for \(r_3(N)\) up to constant factors.

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Replay material: source only

3Evidence

Replay package: source only

A verification source is cited. This record has no executable replay attached.

Verification source: www.erdosproblems.com ↗, See dataset.references[0] for the exact external source and locator.

4How it connects

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Recorded for

Machine-readable record

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  "ref": "R1206",
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  "slug": "erdos-problem-142-claim-status-20260731",
  "type": "claim",
  "title": "Current status and unresolved remainder",
  "summary": "OPEN as of 2026-07-31. The maintained Erdős Problems database at commit 8138974387d9030542daabe67faaa33eff9356f8 lists Problem 142 as open. The unresolved remainder is the full displayed statement. Give a rigorous proof or counterexample that completely resolves this statement: Erdős Problem 142: For a positive integer \\(N\\), let \\(r_3(N)\\) denote the largest possible cardinality of a subset of \\(\\{1, 2, \\dots, N\\}\\) that contains no non-trivial 3-term arithmetic progression. A 3-term arithmetic progression is called non-trivial if its terms are distinct. Determine whether there exists a function \\(f: \\mathbb{N} \\to \\mathbb{R}\\) such that \\(r_3(N) = \\Theta(f(N))\\) as \\(N \\to \\infty\\), and if so, identify such a function. That is, find an explicit asymptotic formula for \\(r_3(N)\\) up to constant factors.",
  "relevance": "For erdos problem 142, pins the dated research frontier: OPEN as of 2026-07-31. The maintained Erdős Problems database at commit 8138974387d9030542daabe67faaa33eff9356f8 lists Problem 142 as open. The unresolved remainder is the full displayed statement. Give a rigorous proof or counterexample that completely resolves this statement: Erdős Problem 142.",
  "relevance_source": "recorded",
  "body": "OPEN as of 2026-07-31. The maintained Erdős Problems database at commit 8138974387d9030542daabe67faaa33eff9356f8 lists Problem 142 as open. The unresolved remainder is the full displayed statement.\n\nA complete resolution must satisfy this condition: Give a rigorous proof or counterexample that completely resolves this statement: Erdős Problem 142: For a positive integer \\(N\\), let \\(r_3(N)\\) denote the largest possible cardinality of a subset of \\(\\{1, 2, \\dots, N\\}\\) that contains no non-trivial 3-term arithmetic progression. A 3-term arithmetic progression is called non-trivial if its terms are distinct. Determine whether there exists a function \\(f: \\mathbb{N} \\to \\mathbb{R}\\) such that \\(r_3(N) = \\Theta(f(N))\\) as \\(N \\to \\infty\\), and if so, identify such a function. That is, find an explicit asymptotic formula for \\(r_3(N)\\) up to constant factors.",
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  "models": [],
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      "slug": "R1205",
      "title": "Resolve the stated acceptance condition",
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6Provenance

View source, identifiers, and projection details

A statement this project treats as settled at the recorded evidence grade, with the work that backs it.

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