TheoremDB

Problem packetResearch packetR1356

R1356Sourced evidence

Current checked status and unresolved remainder

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Authored summary

UNKNOWN as of 2026-07-27. The MathOverflow answers give upper and lower consistency bounds and say the exact strength is open. Later checked problem lists continue to ask for the missing comparison, but the audit did not locate a definitive current survey.

The record cites sources for its explanation.

Recorded status: reported

Recorded scope: No scope is recorded.

Originating problem: Consistency strength of projective Ramsey regularity

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

2Authored explanation

A dated independent review on 2026-08-01 checked the structured sources below, the complete visible source discussion, exact-title and equivalent-formulation searches, and the current TheoremDB corpus. On 2026-07-27 both MathOverflow answers and all comments were checked. They describe a gap between known consistency upper and lower bounds rather than an equiconsistency theorem. The assertion quantifies over all finite projective levels at once. Results for a fixed level, for analytic sets, or for lightface definability do not automatically settle it. Later open-question notes by Khomskii and set-theory seminar notes were checked for the same Ramsey regularity problem. They continue to record an unresolved consistency-strength gap. The base theory and the precise meaning of projective parameters affect consistency calibrations. This record fixes \(\mathsf{ZFC}\) and boldface projective subsets of the standard Polish space \([\omega]^\omega\). Trap: Solovay-model results about all sets of reals often use \(\mathsf{ZF}+\mathsf{DC}\) without full choice. They cannot be transferred to the \(\mathsf{ZFC}\) statement without a separate argument.

A complete resolution must satisfy: Prove both relative-consistency directions between \(\mathsf{ZFC}\) plus projective Ramsey regularity and a precisely stated standard large-cardinal theory, thereby fixing the exact consistency strength. For the named subquestion, prove equiconsistency with one inaccessible cardinal or give strictly sharper matching upper and lower bounds that refute that calibration.

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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: mathoverflow.net ↗, Dataset references and independent 2026-08-01 status search.

4How it connects

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Machine-readable record

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  "ref": "R1356",
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  "slug": "projective-sets-ramsey-consistency-strength-status-20260801",
  "type": "claim",
  "title": "Current checked status and unresolved remainder",
  "summary": "UNKNOWN as of 2026-07-27. The MathOverflow answers give upper and lower consistency bounds and say the exact strength is open. Later checked problem lists continue to ask for the missing comparison, but the audit did not locate a definitive current survey.",
  "relevance": "Records the strongest checked neighboring results and the exact remainder future work must settle.",
  "relevance_source": "recorded",
  "body": "A dated independent review on 2026-08-01 checked the structured sources below, the complete visible source discussion, exact-title and equivalent-formulation searches, and the current TheoremDB corpus. On 2026-07-27 both MathOverflow answers and all comments were checked. They describe a gap between known consistency upper and lower bounds rather than an equiconsistency theorem. The assertion quantifies over all finite projective levels at once. Results for a fixed level, for analytic sets, or for lightface definability do not automatically settle it. Later open-question notes by Khomskii and set-theory seminar notes were checked for the same Ramsey regularity problem. They continue to record an unresolved consistency-strength gap. The base theory and the precise meaning of projective parameters affect consistency calibrations. This record fixes \\(\\mathsf{ZFC}\\) and boldface projective subsets of the standard Polish space \\([\\omega]^\\omega\\). Trap: Solovay-model results about all sets of reals often use \\(\\mathsf{ZF}+\\mathsf{DC}\\) without full choice. They cannot be transferred to the \\(\\mathsf{ZFC}\\) statement without a separate argument.\n\nA complete resolution must satisfy: Prove both relative-consistency directions between \\(\\mathsf{ZFC}\\) plus projective Ramsey regularity and a precisely stated standard large-cardinal theory, thereby fixing the exact consistency strength. For the named subquestion, prove equiconsistency with one inaccessible cardinal or give strictly sharper matching upper and lower bounds that refute that calibration.",
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    "locator": "Dataset references and independent 2026-08-01 status search."
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6Provenance

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

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