{ "id": "2010.03474", "version": "v1", "published": "2020-10-07T15:24:03.000Z", "updated": "2020-10-07T15:24:03.000Z", "title": "Cycles for rational maps over global function fields with one prime of bad reduction", "authors": [ "Silvia Fabiani" ], "comment": "23 pages, 3 figures. Comments are welcome", "categories": [ "math.NT", "math.DS" ], "abstract": "Let $K$ be a global function field of characteristic $p$ and degree $D$ over $\\mathbb F_{p}(t)$. We consider dynamical systems over the projective line $\\mathbb P^1(K)$ defined by rational maps with at most one prime of bad reduction. The main result is an optimal bound for cycle lengths that only depends on $p$ and $D$. A bound for the cardinality of finite orbits is given as well. Our method is based on a careful analysis (for every prime of good reduction) of the $\\mathfrak p$-adic distances between points belonging to the same finite orbit, in part motivated by previous work by Canci and Paladino. Valuable insight is provided by a certain family of polynomials. In this case we also gain a good deal of information about the structure and size of the set of periodic points for polynomials of given degree.", "revisions": [ { "version": "v1", "updated": "2020-10-07T15:24:03.000Z" } ], "analyses": { "subjects": [ "37P05", "37P35" ], "keywords": [ "global function field", "bad reduction", "rational maps", "finite orbit", "periodic points" ], "note": { "typesetting": "TeX", "pages": 23, "language": "en", "license": "arXiv", "status": "editable" } } }