{ "id": "0805.1273", "version": "v1", "published": "2008-05-09T03:55:53.000Z", "updated": "2008-05-09T03:55:53.000Z", "title": "Bell Polynomials and $k$-generalized Dyck Paths", "authors": [ "Toufik Mansour", "Yidong Sun" ], "comment": "15pages, 1 figure. To appear in Discrete Applied Mathematics", "doi": "10.1016/j.dam.2007.10.009", "categories": [ "math.CO" ], "abstract": "A {\\em k-generalized Dyck path} of length $n$ is a lattice path from $(0,0)$ to $(n,0)$ in the plane integer lattice $\\mathbb{Z}\\times\\mathbb{Z}$ consisting of horizontal-steps $(k, 0)$ for a given integer $k\\geq 0$, up-steps $(1,1)$, and down-steps $(1,-1)$, which never passes below the x-axis. The present paper studies three kinds of statistics on $k$-generalized Dyck paths: \"number of $u$-segments\", \"number of internal $u$-segments\" and \"number of $(u,h)$-segments\". The Lagrange inversion formula is used to represent the generating function for the number of $k$-generalized Dyck paths according to the statistics as a sum of the partial Bell polynomials or the potential polynomials. Many important special cases are considered leading to several surprising observations. Moreover, enumeration results related to $u$-segments and $(u,h)$-segments are also established, which produce many new combinatorial identities, and specially, two new expressions for Catalan numbers.", "revisions": [ { "version": "v1", "updated": "2008-05-09T03:55:53.000Z" } ], "analyses": { "subjects": [ "05A05", "05A15" ], "keywords": [ "generalized dyck paths", "important special cases", "partial bell polynomials", "lagrange inversion formula", "plane integer lattice" ], "tags": [ "journal article" ], "note": { "typesetting": "TeX", "pages": 15, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2008arXiv0805.1273M" } } }