{
  "id": "1102.1954",
  "version": "v3",
  "published": "2011-02-09T19:57:19.000Z",
  "updated": "2011-11-24T10:34:57.000Z",
  "title": "Countable open and closed functions",
  "authors": [
    "Alexey Ostrovsky"
  ],
  "comment": "5 pages. arXiv admin note: substantial text overlap with arXiv:1102.3253",
  "categories": [
    "math.GN"
  ],
  "abstract": "We define two natural classes of functions, called 2-open and 2-closed, that are closest to open and closed functions. We show that they have the following property: there are $X_i \\subset X$ $ (i=1,2,...$) such that $f|X_i$ are open or closed functions onto $f(X_i)$ and $f(X_i)$ cover $Y.$",
  "revisions": [
    {
      "version": "v3",
      "updated": "2011-11-24T10:34:57.000Z"
    }
  ],
  "analyses": {
    "subjects": [
      "54C10",
      "26A21",
      "54E40",
      "54H05"
    ],
    "keywords": [
      "closed functions",
      "countable open",
      "natural classes"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 5,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2011arXiv1102.1954O"
    }
  }
}