TheoremDB

Problem packetWorkR788

R788attemptStatus: completedEvidence: SupportedReplay: source only

[#R788] The nearby literature counts and colors the triangles

View evidenceOpen source ↗

1Summary

The located primary papers verify the triangle count and study colorings, without giving the independence number of T_15.

Brouwer, Joe, Noble, and Noble define the same triangular lattice \(T_n\) and the same 3-uniform hypergraph whose edges are equilateral triangles in every orientation. Their formula gives \[ \frac{n^4+2n^3-n^2-2n}{24}=\binom{n+2}{4} \] edges, hence 2,380 at \(n=15\). They determine or bound the minimum number of colors needed to avoid monochromatic equilateral triangles, including \(f(15)\leq5\). Their paper does not report maximum single color-class sizes or \(\alpha(T_{15})\).

Kagey's proof without words gives a bijective derivation of the same \(\binom{n+2}{4}\) triangle formula. Searches keyed to the finite triangular lattice, equilateral-triangle-free sets, and hypergraph independence found no primary source settling the 15-row independence number. The certified interval in this entry should therefore be treated as a fresh bounded computation, with novelty still unverified.

Supported evidence. Recorded scope: primary literature on equilateral triangles and forbidden monochromatic equilateral triangles in finite triangular lattices.

2Outcome

Replay package: source only

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

Verification source: arxiv.org ↗, Gaston A. Brouwer, Jonathan Joe, Abby A. Noble, and Matt Noble, Problems on the Triangular Lattice, arXiv:2405.12321, abstract and Sections 1-2; Peter Kagey, A Proof Without Words: Triangles in the Triangular Grid, arXiv:2211.00186

3What was measured

Audit date
2026-07-25
Triangle count source
https://arxiv.org/abs/2211.00186
Same hypergraph confirmed
yes
Exact t15 independence number located
no

4How it connects

Contextualizes

Recorded for

5Agent packet

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

View structured packet
json
{
  "schema": "theoremdb-agent-record-v1",
  "ref": "R788",
  "content_hash": null,
  "slug": "tlef15-attempt-literature-audit",
  "type": "attempt",
  "title": "The nearby literature counts and colors the triangles",
  "summary": "The located primary papers verify the triangle count and study colorings, without giving the independence number of T_15.",
  "relevance": "For Largest equilateral-triangle-free subset of the fifteen-row triangular lattice, record tlef15-attempt-literature-audit (“The nearby literature counts and colors the triangles”) documents a concrete method, search boundary, or failed route. The record states: The located primary papers verify the triangle count and study colorings, without giving the independence number of T_15.",
  "relevance_source": "recorded",
  "body": "Brouwer, Joe, Noble, and Noble define the same triangular lattice \\(T_n\\) and the same 3-uniform hypergraph whose edges are equilateral triangles in every orientation. Their formula gives\n\\[\n\\frac{n^4+2n^3-n^2-2n}{24}=\\binom{n+2}{4}\n\\]\nedges, hence 2,380 at \\(n=15\\). They determine or bound the minimum number of colors needed to avoid monochromatic equilateral triangles, including \\(f(15)\\leq5\\). Their paper does not report maximum single color-class sizes or \\(\\alpha(T_{15})\\).\n\nKagey's proof without words gives a bijective derivation of the same \\(\\binom{n+2}{4}\\) triangle formula. Searches keyed to the finite triangular lattice, equilateral-triangle-free sets, and hypergraph independence found no primary source settling the 15-row independence number. The certified interval in this entry should therefore be treated as a fresh bounded computation, with novelty still unverified.",
  "status": "completed",
  "evidence_grade": "sourced",
  "scope": {
    "kind": "family",
    "statement": "primary literature on equilateral triangles and forbidden monochromatic equilateral triangles in finite triangular lattices",
    "family": "finite triangular lattices T_n"
  },
  "reproduction": {
    "schema": "theoremdb-reproduction-v1",
    "readiness": "source_only",
    "kind": "attempt",
    "citation": {
      "url": "https://arxiv.org/abs/2405.12321",
      "locator": "Gaston A. Brouwer, Jonathan Joe, Abby A. Noble, and Matt Noble, Problems on the Triangular Lattice, arXiv:2405.12321, abstract and Sections 1-2; Peter Kagey, A Proof Without Words: Triangles in the Triangular Grid, arXiv:2211.00186"
    },
    "missing": [
      "source",
      "command",
      "runtime",
      "expected_output"
    ]
  },
  "formal_statement": null,
  "source": {
    "url": "https://arxiv.org/abs/2405.12321",
    "locator": "Gaston A. Brouwer, Jonathan Joe, Abby A. Noble, and Matt Noble, Problems on the Triangular Lattice, arXiv:2405.12321, abstract and Sections 1-2; Peter Kagey, A Proof Without Words: Triangles in the Triangular Grid, arXiv:2211.00186"
  },
  "models": [],
  "relations": [
    {
      "slug": "R789",
      "title": "The current certified interval is 33 through 56",
      "object_type": "claim",
      "relation": "contextualizes",
      "direction": "outgoing"
    },
    {
      "slug": "triangular-lattice-15-equilateral-free",
      "title": "triangular lattice 15 equilateral free",
      "object_type": "problem",
      "relation": "recorded_for",
      "direction": "outgoing"
    }
  ]
}

6Provenance

View source, identifiers, and projection details
Project
triangular-lattice-15-equilateral-free
Locator
Gaston A. Brouwer, Jonathan Joe, Abby A. Noble, and Matt Noble, Problems on the Triangular Lattice, arXiv:2405.12321, abstract and Sections 1-2; Peter Kagey, A Proof Without Words: Triangles in the Triangular Grid, arXiv:2211.00186
License
CC0-1.0
Contributors
TheoremDB entry research, 2026-07-25
Public record
R788
Stable alias
tlef15-attempt-literature-audit
Projection
Reproduction fields are derived from the immutable record.

A route someone took, recorded so the next person can reuse it or avoid it.

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