"Petersen graph" meaning in English

{
  "etymology_text": "Named after Julius Petersen, who in 1898 constructed it to be the smallest bridgeless cubic graph with no three-edge-coloring.",
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      "glosses": [
        "An undirected graph with 10 vertices and 15 edges, serving as a simple example and counterexample for many problems in graph theory."
      ],
      "id": "en-Petersen_graph-en-noun-QobMEh31",
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          "graph theory"
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          "undirected graph",
          "undirected graph"
        ],
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          "vertices",
          "vertex"
        ],
        [
          "edge",
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          "example",
          "example"
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      "raw_glosses": [
        "(graph theory) An undirected graph with 10 vertices and 15 edges, serving as a simple example and counterexample for many problems in graph theory."
      ],
      "topics": [
        "graph-theory",
        "mathematics",
        "sciences"
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        "Julius Petersen"
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  ],
  "word": "Petersen graph"
}

{
  "etymology_text": "Named after Julius Petersen, who in 1898 constructed it to be the smallest bridgeless cubic graph with no three-edge-coloring.",
  "forms": [
    {
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      "tags": [
        "plural"
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        "An undirected graph with 10 vertices and 15 edges, serving as a simple example and counterexample for many problems in graph theory."
      ],
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          "graph theory",
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        "(graph theory) An undirected graph with 10 vertices and 15 edges, serving as a simple example and counterexample for many problems in graph theory."
      ],
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        "graph-theory",
        "mathematics",
        "sciences"
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