"Euler characteristic" meaning in English

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  "lang_code": "en",
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      "examples": [
        {
          "text": "A polygon's or polyhedron's Euler characteristic is just the number of corners minus the number of edges plus the number of faces.",
          "type": "example"
        }
      ],
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        "The sum of even-dimensional Betti numbers minus the sum of odd-dimensional ones."
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          "-dimensional",
          "-dimensional"
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          "Betti number",
          "Betti number"
        ],
        [
          "minus",
          "minus"
        ],
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          "odd",
          "odd"
        ]
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      "raw_glosses": [
        "(topology, of a topological space) The sum of even-dimensional Betti numbers minus the sum of odd-dimensional ones."
      ],
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        "of a topological space"
      ],
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        "mathematics",
        "sciences",
        "topology"
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        "Euler characteristic"
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  "word": "Euler characteristic"
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      "examples": [
        {
          "text": "A polygon's or polyhedron's Euler characteristic is just the number of corners minus the number of edges plus the number of faces.",
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        }
      ],
      "glosses": [
        "The sum of even-dimensional Betti numbers minus the sum of odd-dimensional ones."
      ],
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          "sum"
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        ],
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          "Betti number",
          "Betti number"
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          "minus",
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        ],
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          "odd",
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        "(topology, of a topological space) The sum of even-dimensional Betti numbers minus the sum of odd-dimensional ones."
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        "mathematics",
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