TheoremDB

Problem packetResearch packetR1545

R1545Sourced evidence

Dated status and exact unresolved remainder

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Authored summary

Unresolved in this packet after the dated source check. Strongest checked result: The MathOverflow and Mathematics Stack Exchange pages have no solution. The source author reported in 2021 that the author of the four-cell theorem knew of no later progress, and no subsequent exact classification was found. Exact unresolved remainder: Prove that every five-element subset A of Z^2 tiles by lattice translations and square-lattice symmetries, or exhibit a specific five-element A and prove that no such tiling exists. A positive computational classification must state a finite reduction for arbitrarily separated cells and provide periodic fundamental-domain certificates for every reduced class; bounded-box enumeration alone is insufficient.

The record cites sources for its explanation.

Recorded status: reported

Recorded scope: No scope is recorded.

Originating problem: Plane tilings by every five-cell lattice animal

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

2Authored explanation

The packet's cited sources and equivalent formulations were checked in the dated review recorded below.

Strongest checked result: The MathOverflow and Mathematics Stack Exchange pages have no solution. The source author reported in 2021 that the author of the four-cell theorem knew of no later progress, and no subsequent exact classification was found.

Exact unresolved remainder: Prove that every five-element subset A of Z^2 tiles by lattice translations and square-lattice symmetries, or exhibit a specific five-element A and prove that no such tiling exists. A positive computational classification must state a finite reduction for arbitrarily separated cells and provide periodic fundamental-domain certificates for every reduced class; bounded-box enumeration alone is insufficient.

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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 ↗, Full question, answers, and visible comments concerning Plane tilings by every five-cell lattice animal; checked 2026-08-01.

4What was measured

5How it connects

Replaces

Recorded for

Machine-readable record

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  "ref": "R1545",
  "content_hash": null,
  "slug": "five-cell-lattice-animal-plane-tiling-status-packet-quality-20260801",
  "type": "claim",
  "title": "Dated status and exact unresolved remainder",
  "summary": "Unresolved in this packet after the dated source check. Strongest checked result: The MathOverflow and Mathematics Stack Exchange pages have no solution. The source author reported in 2021 that the author of the four-cell theorem knew of no later progress, and no subsequent exact classification was found. Exact unresolved remainder: Prove that every five-element subset A of Z^2 tiles by lattice translations and square-lattice symmetries, or exhibit a specific five-element A and prove that no such tiling exists. A positive computational classification must state a finite reduction for arbitrarily separated cells and provide periodic fundamental-domain certificates for every reduced class; bounded-box enumeration alone is insufficient.",
  "relevance": "For Plane tilings by every five-cell lattice animal, this successor gives readable dated status prose and the exact remaining research boundary.",
  "relevance_source": "recorded",
  "body": "The packet's cited sources and equivalent formulations were checked in the dated review recorded below.\n\nStrongest checked result: The MathOverflow and Mathematics Stack Exchange pages have no solution. The source author reported in 2021 that the author of the four-cell theorem knew of no later progress, and no subsequent exact classification was found.\n\nExact unresolved remainder: Prove that every five-element subset A of Z^2 tiles by lattice translations and square-lattice symmetries, or exhibit a specific five-element A and prove that no such tiling exists. A positive computational classification must state a finite reduction for arbitrarily separated cells and provide periodic fundamental-domain certificates for every reduced class; bounded-box enumeration alone is insufficient.",
  "status": "reported",
  "evidence_grade": "sourced",
  "scope": null,
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    "kind": "claim",
    "citation": {
      "url": "https://mathoverflow.net/questions/380490/does-every-5-celled-animal-tile-the-plane",
      "locator": "Full question, answers, and visible comments concerning Plane tilings by every five-cell lattice animal; checked 2026-08-01."
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  "formal_statement": null,
  "source": {
    "url": "https://mathoverflow.net/questions/380490/does-every-5-celled-animal-tile-the-plane",
    "locator": "Full question, answers, and visible comments concerning Plane tilings by every five-cell lattice animal; checked 2026-08-01."
  },
  "models": [],
  "continuation": null,
  "relations": [
    {
      "slug": "R1311",
      "title": "Current checked status and unresolved remainder",
      "object_type": "claim",
      "relation": "supersedes",
      "direction": "outgoing",
      "metadata": {
        "reason": "Replaces unreadable status prose with the dated review from 2026-08-01."
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    },
    {
      "slug": "five-cell-lattice-animal-plane-tiling",
      "title": "five cell lattice animal plane tiling",
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7Provenance

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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