TheoremDB

Problem packetResearch packetR596

R596Sourced evidence

Five order-12 MOLS are constructed, while eleven would settle the problem

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Authored summary

A 1960 construction proves N(12) at least 5; the universal upper bound is 11, and equality is equivalent to an order-12 plane.

The record cites sources for its explanation.

Recorded status: established

Recorded scope: the maximum number N(12) of pairwise mutually orthogonal Latin squares of order 12

Complete recorded scope and conditions
{
  "kind": "bounded",
  "statement": "the maximum number N(12) of pairwise mutually orthogonal Latin squares of order 12",
  "bounds": {
    "order": {
      "min": 12,
      "max": 12
    },
    "constructed_squares": {
      "min": 5,
      "max": 5
    },
    "complete_set_size": {
      "min": 11,
      "max": 11
    }
  },
  "exhaustive": false
}

Originating problem: A projective plane of order 12

Authored record and scope
Authored title
Five order-12 MOLS are constructed, while eleven would settle the problem
Record type
claim
Stored status
established
Evidence grade
sourced
Recorded scope data
{ "kind": "bounded", "statement": "the maximum number N(12) of pairwise mutually orthogonal Latin squares of order 12", "bounds": { "order": { "min": 12, "max": 12 }, "constructed_squares": { "min": 5, "max": 5 }, "complete_set_size": { "min": 11, "max": 11 } }, "exhaustive": false }

2Authored explanation

Let \(N(12)\) be the largest size of a pairwise mutually orthogonal family of Latin squares of order 12. Bose, Chakravarti, and Knuth explicitly construct two families of five in their 1960 paper, proving \[ N(12)\ge5. \] The universal bound gives \(N(12)\le11\). A family of 11 is a complete family, equivalent to an affine plane and hence to a projective plane of order 12.

Thus the published five-square construction supplies a concrete partial object. Extending any compatible family to 11 would prove existence. A proof that all complete-family branches fail would prove nonexistence.

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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: doi.org ↗, R. C. Bose, I. M. Chakravarti, and D. E. Knuth, On Methods of Constructing Sets of Mutually Orthogonal Latin Squares Using a Computer. I, Technometrics 2(4) (1960), 507-516, abstract, Figure 1, and Table 2

4What was measured

5How it connects

Informs

Recorded for

Machine-readable record

Copy the structured record when continuing this work with an agent.

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  "ref": "R596",
  "content_hash": null,
  "slug": "pp12-claim-five-mols-lower-bound",
  "type": "claim",
  "title": "Five order-12 MOLS are constructed, while eleven would settle the problem",
  "summary": "A 1960 construction proves N(12) at least 5; the universal upper bound is 11, and equality is equivalent to an order-12 plane.",
  "relevance": "For A projective plane of order 12, record pp12-claim-five-mols-lower-bound (“Five order-12 MOLS are constructed, while eleven would settle the problem”) records a bound, answer, status fact, or structural consequence. The record states: A 1960 construction proves N(12) at least 5; the universal upper bound is 11, and equality is equivalent to an order-12 plane.",
  "relevance_source": "recorded",
  "body": "Let \\(N(12)\\) be the largest size of a pairwise mutually orthogonal family of Latin squares of order 12. Bose, Chakravarti, and Knuth explicitly construct two families of five in their 1960 paper, proving\n\\[\nN(12)\\ge5.\n\\]\nThe universal bound gives \\(N(12)\\le11\\). A family of 11 is a complete family, equivalent to an affine plane and hence to a projective plane of order 12.\n\nThus the published five-square construction supplies a concrete partial object. Extending any compatible family to 11 would prove existence. A proof that all complete-family branches fail would prove nonexistence.",
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      "order": {
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    "url": "https://doi.org/10.1080/00401706.1960.10489916",
    "locator": "R. C. Bose, I. M. Chakravarti, and D. E. Knuth, On Methods of Constructing Sets of Mutually Orthogonal Latin Squares Using a Computer. I, Technometrics 2(4) (1960), 507-516, abstract, Figure 1, and Table 2"
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  "relations": [
    {
      "slug": "R597",
      "title": "Existence at order 12 remains open",
      "object_type": "claim",
      "relation": "informs",
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    },
    {
      "slug": "projective-plane-order-12",
      "title": "projective plane order 12",
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7Provenance

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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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