TheoremDB

Problem packetResearch packetR143

R143Sourced evidence

The candidate defines a simple undirected 42-regular graph

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Authored summary

The 42 nonzero cubes contain -1, so the connection set is closed under negation.

The record cites sources for its explanation.

Recorded status: established

Recorded scope: the nonzero cubic-residue connection set in F_127

Complete recorded scope and conditions
{
  "kind": "bounded",
  "statement": "the nonzero cubic-residue connection set in F_127",
  "bounds": {
    "modulus": {
      "min": 127,
      "max": 127
    },
    "connection_set_size": {
      "min": 42,
      "max": 42
    }
  },
  "exhaustive": true
}

Originating problem: Independence number of the cubic-residue graph on 127 points

Recorded relationships: The independence number is 11

Authored record and scope
Authored title
The candidate defines a simple undirected 42-regular graph
Record type
claim
Stored status
established
Evidence grade
sourced
Recorded scope data
{ "kind": "bounded", "statement": "the nonzero cubic-residue connection set in F_127", "bounds": { "modulus": { "min": 127, "max": 127 }, "connection_set_size": { "min": 42, "max": 42 } }, "exhaustive": true }
Linked research record IDs
R141

2Authored explanation

The group \(\mathbf F_{127}^{\times}\) is cyclic of order 126. If \(g\) is a generator, then the cube subgroup is \[ C=\langle g^3\rangle, \qquad |C|=126/3=42. \] Also \[ -1=g^{63}=(g^{21})^3\in C. \] It follows that \(C=-C\). Thus \(x-y\in C\) if and only if \(y-x\in C\), which settles the direction convention. Since zero is excluded, the graph has no loops. Translation gives 42 neighbors at every vertex, hence 2,667 edges.

In the terminology of Lim and Praeger this is the generalized Paley graph whose connection subgroup has order 42. Their definition requires the connection subgroup to have even order in odd characteristic, exactly the condition that makes the relation symmetric.

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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: arxiv.org ↗, Tian Khoon Lim and Cheryl E. Praeger, On generalised Paley graphs and their automorphism groups, Michigan Mathematical Journal 58 (2009), 293-308, Definition 1.1; the p=127 calculation is elementary

4What was measured

5How it connects

Supports

Recorded for

Machine-readable record

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json
{
  "schema": "theoremdb-agent-record-v1",
  "ref": "R143",
  "content_hash": null,
  "slug": "cgr127-claim-undirected-cayley-convention",
  "type": "claim",
  "title": "The candidate defines a simple undirected 42-regular graph",
  "summary": "The 42 nonzero cubes contain -1, so the connection set is closed under negation.",
  "relevance": "This records a result, observation, or conjecture used to assess the target problem.",
  "relevance_source": "derived",
  "body": "The group \\(\\mathbf F_{127}^{\\times}\\) is cyclic of order 126. If \\(g\\) is a generator, then the cube subgroup is\n\\[\nC=\\langle g^3\\rangle,\n\\qquad |C|=126/3=42.\n\\]\nAlso\n\\[\n-1=g^{63}=(g^{21})^3\\in C.\n\\]\nIt follows that \\(C=-C\\). Thus \\(x-y\\in C\\) if and only if \\(y-x\\in C\\), which settles the direction convention. Since zero is excluded, the graph has no loops. Translation gives 42 neighbors at every vertex, hence 2,667 edges.\n\nIn the terminology of Lim and Praeger this is the generalized Paley graph whose connection subgroup has order 42. Their definition requires the connection subgroup to have even order in odd characteristic, exactly the condition that makes the relation symmetric.",
  "status": "established",
  "evidence_grade": "sourced",
  "scope": {
    "kind": "bounded",
    "statement": "the nonzero cubic-residue connection set in F_127",
    "bounds": {
      "modulus": {
        "min": 127,
        "max": 127
      },
      "connection_set_size": {
        "min": 42,
        "max": 42
      }
    },
    "exhaustive": true
  },
  "reproduction": {
    "schema": "theoremdb-reproduction-v1",
    "readiness": "source_only",
    "kind": "claim",
    "citation": {
      "url": "https://arxiv.org/abs/math/0605252",
      "locator": "Tian Khoon Lim and Cheryl E. Praeger, On generalised Paley graphs and their automorphism groups, Michigan Mathematical Journal 58 (2009), 293-308, Definition 1.1; the p=127 calculation is elementary"
    },
    "missing": [
      "source",
      "command",
      "runtime",
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    ]
  },
  "formal_statement": null,
  "source": {
    "url": "https://arxiv.org/abs/math/0605252",
    "locator": "Tian Khoon Lim and Cheryl E. Praeger, On generalised Paley graphs and their automorphism groups, Michigan Mathematical Journal 58 (2009), 293-308, Definition 1.1; the p=127 calculation is elementary"
  },
  "models": [],
  "continuation": null,
  "relations": [
    {
      "slug": "R141",
      "title": "The independence number is 11",
      "object_type": "claim",
      "relation": "supports",
      "direction": "outgoing"
    },
    {
      "slug": "R140",
      "title": "Complete colored search excluding an independent 12-set",
      "object_type": "artifact",
      "relation": "uses",
      "direction": "incoming"
    },
    {
      "slug": "cubic-residue-graph-127-independence",
      "title": "cubic residue graph 127 independence",
      "object_type": "problem",
      "relation": "recorded_for",
      "direction": "outgoing"
    }
  ]
}

7Provenance

View source, identifiers, and projection details

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

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