TheoremDB

Problem packetWorkR95

R95claimStatus: reportedEvidence: SupportedReplay: source only

[#R95] The checked published interval is 27 through 57

claim. The elementary interaction bound and a published 57-row construction give 27 <= CAN(3,15,3) <= 57; the exact value remains unresolved in the sources reviewed.

View evidenceOpen source ↗

1Summary

A strength-three ternary covering array with 15 columns must display all \(3^3=27\) ordered triples in every choice of three columns. One row supplies one triple for a fixed column choice, so every such array has at least 27 rows.

Avila-George, Torres-Jimenez, Hernandez, and Gonzalez-Hernandez report 57 rows for \(k=15\) in Table 2(a) of their 2012 primary paper. Their table labels this value as the best-known solution before their cooperative simulated-annealing experiment and reproduces 57 in the experiment. This gives the sourced upper bound \[ 27\le \operatorname{CAN}(3,15,3)\le57. \] The paper says its arrays were deposited in the Cinvestav Covering Array Repository and verified with a separate tool. The repository now requires access, and the audit recovered no public 57-row payload or nonexistence certificate for 56 rows. The exact value should therefore remain open in TheoremDB.

Supported evidence. Recorded scope: the homogeneous ternary covering-array number CAN(3,15,3).

2Evidence

Replay package: source only

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

Verification source: doi.org ↗, J. Avila-George, J. Torres-Jimenez, V. Hernandez, and N. Gonzalez-Hernandez, New Bounds for Ternary Covering Arrays Using a Parallel Simulated Annealing, Mathematical Problems in Engineering 2012, Article 897027, Table 2(a), row t=3 and k=15; repository and verification statement in Section 6

3What was measured

Notation
CAN(3,15,3)
Lower bound
27
Upper bound
57
Gap
30
Exact value known
no
Lower bound method
For any fixed three columns, 27 distinct ordered triples must occur and each row realizes one.
Upper bound method
Published covering-array construction, reported as 57 rows in the primary paper.
Upper bound witness publicly recovered
no
Audit date
2026-07-25
Verified witness record
ca3153-claim-nist-80-row-array

4How it connects

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": "R95",
  "content_hash": null,
  "slug": "ca3153-claim-published-interval",
  "type": "claim",
  "title": "The checked published interval is 27 through 57",
  "summary": "The elementary interaction bound and a published 57-row construction give 27 <= CAN(3,15,3) <= 57; the exact value remains unresolved in the sources reviewed.",
  "relevance": "For Exact value of CAN(3,15,3), record ca3153-claim-published-interval (“The checked published interval is 27 through 57”) records a bound, answer, status fact, or structural consequence. The record states: The elementary interaction bound and a published 57-row construction give 27 <= CAN(3,15,3) <= 57; the exact value remains unresolved in the sources reviewed.",
  "relevance_source": "recorded",
  "body": "A strength-three ternary covering array with 15 columns must display all \\(3^3=27\\) ordered triples in every choice of three columns. One row supplies one triple for a fixed column choice, so every such array has at least 27 rows.\n\nAvila-George, Torres-Jimenez, Hernandez, and Gonzalez-Hernandez report 57 rows for \\(k=15\\) in Table 2(a) of their 2012 primary paper. Their table labels this value as the best-known solution before their cooperative simulated-annealing experiment and reproduces 57 in the experiment. This gives the sourced upper bound\n\\[\n27\\le \\operatorname{CAN}(3,15,3)\\le57.\n\\]\nThe paper says its arrays were deposited in the Cinvestav Covering Array Repository and verified with a separate tool. The repository now requires access, and the audit recovered no public 57-row payload or nonexistence certificate for 56 rows. The exact value should therefore remain open in TheoremDB.",
  "status": "reported",
  "evidence_grade": "sourced",
  "scope": {
    "kind": "bounded",
    "statement": "the homogeneous ternary covering-array number CAN(3,15,3)",
    "bounds": {
      "strength": {
        "min": 3,
        "max": 3
      },
      "columns": {
        "min": 15,
        "max": 15
      },
      "alphabet_size": {
        "min": 3,
        "max": 3
      }
    },
    "exhaustive": false
  },
  "reproduction": {
    "schema": "theoremdb-reproduction-v1",
    "readiness": "source_only",
    "kind": "claim",
    "citation": {
      "url": "https://doi.org/10.1155/2012/897027",
      "locator": "J. Avila-George, J. Torres-Jimenez, V. Hernandez, and N. Gonzalez-Hernandez, New Bounds for Ternary Covering Arrays Using a Parallel Simulated Annealing, Mathematical Problems in Engineering 2012, Article 897027, Table 2(a), row t=3 and k=15; repository and verification statement in Section 6"
    },
    "missing": [
      "source",
      "command",
      "runtime",
      "expected_output"
    ]
  },
  "formal_statement": null,
  "source": {
    "url": "https://doi.org/10.1155/2012/897027",
    "locator": "J. Avila-George, J. Torres-Jimenez, V. Hernandez, and N. Gonzalez-Hernandez, New Bounds for Ternary Covering Arrays Using a Parallel Simulated Annealing, Mathematical Problems in Engineering 2012, Article 897027, Table 2(a), row t=3 and k=15; repository and verification statement in Section 6"
  },
  "models": [],
  "relations": [
    {
      "slug": "R94",
      "title": "The completed NIST 80-row array covers every interaction",
      "object_type": "claim",
      "relation": "supports",
      "direction": "incoming"
    },
    {
      "slug": "covering-array-3-15-3",
      "title": "covering array 3 15 3",
      "object_type": "problem",
      "relation": "recorded_for",
      "direction": "outgoing"
    }
  ]
}

6Provenance

View source, identifiers, and projection details
Project
covering-array-3-15-3
Locator
J. Avila-George, J. Torres-Jimenez, V. Hernandez, and N. Gonzalez-Hernandez, New Bounds for Ternary Covering Arrays Using a Parallel Simulated Annealing, Mathematical Problems in Engineering 2012, Article 897027, Table 2(a), row t=3 and k=15; repository and verification statement in Section 6
License
CC0-1.0
Contributors
TheoremDB entry research, 2026-07-25
Public record
R95
Stable alias
ca3153-claim-published-interval
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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