{ "id": "math/0206169", "version": "v1", "published": "2002-06-17T20:54:26.000Z", "updated": "2002-06-17T20:54:26.000Z", "title": "Some statistics on restricted 132 involutions", "authors": [ "O. Guibert", "T. Mansour" ], "comment": "22 pages", "categories": [ "math.CO" ], "abstract": "In [GM] Guibert and Mansour studied involutions on n letters avoiding (or containing exactly once) 132 and avoiding (or containing exactly once) an arbitrary pattern on k letters. They also established a bijection between 132-avoiding involutions and Dyck word prefixes of same length. Extending this bijection to bilateral words allows to determine more parameters; in particular, we consider the number of inversions and rises of the involutions onto the words. This is the starting point for considering two different directions: even/odd involutions and statistics of some generalized patterns. Thus we first study generating functions for the number of even or odd involutions on n letters avoiding (or containing exactly once) 132 and avoiding (or containing exactly once) an arbitrary pattern $\\tau$ on k letters. In several interesting cases the generating function depends only on k and is expressed via Chebyshev polynomials of the second kind. Next, we consider other statistics on 132-avoiding involutions by counting an occurrences of some generalized patterns, related to the enumeration according to the number of rises.", "revisions": [ { "version": "v1", "updated": "2002-06-17T20:54:26.000Z" } ], "analyses": { "keywords": [ "statistics", "containing", "dyck word prefixes", "first study generating functions", "generalized patterns" ], "note": { "typesetting": "TeX", "pages": 22, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2002math......6169G" } } }