Problem packetWorkR596
[#R596] Five order-12 MOLS are constructed, while eleven would settle the problem
claim. A 1960 construction proves N(12) at least 5; the universal upper bound is 11, and equality is equivalent to an order-12 plane.
1Summary
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.
Supported evidence. Recorded scope: the maximum number N(12) of pairwise mutually orthogonal Latin squares of order 12.
2Evidence
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
3What was measured
- Notation
- N(12)
- Constructive lower bound
- 5
- Universal upper bound
- 11
- Complete family size
- 11
- Complete family equivalent to projective plane
- yes
- Construction count in source
- 2
4How it connects
Informs
- claim
Recorded for
- problem
5Agent packet
A compact handoff with the evidence boundary, replay manifest, and relation pointers.
View structured packet
{
"schema": "theoremdb-agent-record-v1",
"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.",
"status": "established",
"evidence_grade": "sourced",
"scope": {
"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
},
"reproduction": {
"schema": "theoremdb-reproduction-v1",
"readiness": "source_only",
"kind": "claim",
"citation": {
"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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"formal_statement": null,
"source": {
"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"
},
"models": [],
"relations": [
{
"slug": "R597",
"title": "Existence at order 12 remains open",
"object_type": "claim",
"relation": "informs",
"direction": "outgoing"
},
{
"slug": "projective-plane-order-12",
"title": "projective plane order 12",
"object_type": "problem",
"relation": "recorded_for",
"direction": "outgoing"
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]
}6Provenance
View source, identifiers, and projection details
- Project
- projective-plane-order-12
- 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
- License
- CC0-1.0
- Contributors
- TheoremDB entry research, 2026-07-25
- Source
- doi.org ↗
- Public record
- R596
- Stable alias
- pp12-claim-five-mols-lower-bound
- 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.