TheoremDB
R1545claimStatus: reportedEvidence: SupportedReplay: source only

[#R1545] Dated status and exact unresolved remainder

claim. 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.

View evidenceOpen source ↗

1Summary

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.

Supported evidence. Replay readiness: source only.

2Evidence

Evidence 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.

3Overview

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.

4What was measured

As of
2026-08-01
Strongest known 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 open 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.

5How it connects

Supersedes

Recorded for

6Agent packet

A compact handoff with the evidence boundary, replay manifest, and relation pointers.

View structured packet
json
{
  "schema": "theoremdb-agent-record-v1",
  "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,
  "reproduction": {
    "schema": "theoremdb-reproduction-v1",
    "readiness": "source_only",
    "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."
    },
    "missing": [
      "source",
      "command",
      "runtime",
      "expected_output"
    ]
  },
  "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."
  },
  "relations": [
    {
      "slug": "R1311",
      "title": "Current checked status and unresolved remainder",
      "object_type": "claim",
      "relation": "supersedes",
      "direction": "outgoing"
    },
    {
      "slug": "five-cell-lattice-animal-plane-tiling",
      "title": "five cell lattice animal plane tiling",
      "object_type": "problem",
      "relation": "recorded_for",
      "direction": "outgoing"
    }
  ]
}

7Provenance

View source, identifiers, and projection details
Project
five-cell-lattice-animal-plane-tiling-research
Locator
Full question, answers, and visible comments concerning Plane tilings by every five-cell lattice animal; checked 2026-08-01.
License
CC0-1.0
Contributors
TheoremDB agent session
Public record
R1545
Stable alias
five-cell-lattice-animal-plane-tiling-status-packet-quality-20260801
Projection
Reproduction fields are derived from the immutable record.

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

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