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  "body": "\n## Summary\n\nA content is a size function on a family of sets that is only finitely additive, not countably additive.\nIt is the same idea as a [[finitely additive measure|KFWQ24D9M6]], usually on a [[ring of sets|KWE1DBMN9B]] or a [[semiring of sets|PYH82FMXQ2]].\nContents are the first step toward measures: a content that is also countably additive is a [[premeasure|PV0XXSWFC7]].\nJordan measure is a classical content that is not a measure.\n\n## Explanations\n\n### L1 human\n\nA content gives a size to some sets, so that the size of two disjoint pieces together is the sum of their sizes.\nIt says nothing about cutting a set into infinitely many pieces.\nFor example, the area of finite unions of rectangles in the plane is a content.\nThe [[Jordan measure|0KTGJW1ZTH]] of a bounded region, defined by inner and outer approximation by rectangles, is another one.\n",
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    "kind": "concept",
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    "name": "Content",
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      "wikidata": "Q5165061",
      "wikipedia": "Content (measure theory)"
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    "tag": "PFF8SV6ENB"
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  "link": "https://math2.tamnd.com/node/PFF8SV6ENB/",
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  "markdown": "https://math2.tamnd.com/node/PFF8SV6ENB.md",
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  "name": "Content",
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  "source": "https://github.com/tamnd/math2/blob/main/nodes/PFF/PFF8SV6ENB.md",
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  "tag": "PFF8SV6ENB",
  "uri": "m2://PFF8SV6ENB",
  "url": "https://math2.tamnd.com/wiki/content/",
  "writing": {
    "tag": "PFF8SV6ENB",
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    "level": "W0",
    "next": [
      {
        "what": "an inventory row",
        "note": "the row of the inventory that the node accounts for",
        "have": 0,
        "want": 1
      },
      {
        "what": "a source with a locator",
        "have": 0,
        "want": 1
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