{
  "id": "1008.2375",
  "version": "v1",
  "published": "2010-08-13T19:18:34.000Z",
  "updated": "2010-08-13T19:18:34.000Z",
  "title": "A bijection to count (1-23-4)-avoiding permutations",
  "authors": [
    "David Callan"
  ],
  "comment": "latex, 16 pages",
  "categories": [
    "math.CO"
  ],
  "abstract": "A permutation is (1-23-4)-avoiding if it contains no four entries, increasing left to right, with the middle two adjacent in the permutation. Here we give a 2-variable recurrence for the number of such permutations, improving on the previously known 4-variable recurrence. At the heart of the proof is a bijection from (1-23-4)-avoiding permutations to increasing ordered trees whose leaves, taken in preorder, are also increasing.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2010-08-13T19:18:34.000Z"
    }
  ],
  "analyses": {
    "subjects": [
      "05A15"
    ],
    "keywords": [
      "permutation",
      "recurrence",
      "increasing left",
      "increasing ordered trees"
    ],
    "note": {
      "typesetting": "LaTeX",
      "pages": 16,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2010arXiv1008.2375C"
    }
  }
}