{ "id": "2006.09321", "version": "v1", "published": "2020-06-16T17:05:46.000Z", "updated": "2020-06-16T17:05:46.000Z", "title": "Interval parking functions", "authors": [ "Emma Colaric", "Ryan DeMuse", "Jeremy L. Martin", "Mei Yin" ], "comment": "12 pages", "categories": [ "math.CO" ], "abstract": "Interval parking functions (IPFs) are a generalization of ordinary parking functions in which each car is willing to park only in a fixed interval of spaces. Each interval parking function can be expressed as a pair $(a,b)$, where $a$ is a parking function and $b$ is a dual parking function. We say that a pair of permutations $(x,y)$ is \\emph{reachable} if there is an IPF $(a,b)$ such that $x,y$ are the outcomes of $a,b$, respectively, as parking functions. Reachability is reflexive and antisymmetric, but not in general transitive. We prove that its transitive closure, the \\emph{pseudoreachability order}, is precisely the bubble-sort order on the symmetric group $\\Sym_n$, which can be expressed in terms of the normal form of a permutation in the sense of du~Cloux; in particular, it is isomorphic to the product of chains of lengths $2,\\dots,n$. It is thus seen to be a special case of Armstrong's sorting order, which lies between the Bruhat and (left) weak orders.", "revisions": [ { "version": "v1", "updated": "2020-06-16T17:05:46.000Z" } ], "analyses": { "subjects": [ "05A05", "05A15", "06A07" ], "keywords": [ "interval parking function", "normal form", "symmetric group", "armstrongs sorting order", "special case" ], "note": { "typesetting": "TeX", "pages": 12, "language": "en", "license": "arXiv", "status": "editable" } } }