{ "id": "1407.1573", "version": "v1", "published": "2014-07-07T03:54:13.000Z", "updated": "2014-07-07T03:54:13.000Z", "title": "Portraits of preperiodic points for rational maps", "authors": [ "Dragos Ghioca", "Khoa Nguyen", "Thomas J. Tucker" ], "categories": [ "math.NT", "math.AG", "math.DS" ], "abstract": "Let $K$ be a function field over an algebraically closed field $k$ of characteristic $0$, let $\\varphi\\in K(z)$ be a rational function of degree at least equal to $2$ for which there is no point at which $\\varphi$ is totally ramified, and let $\\alpha\\in K$. We show that for all but finitely many pairs $(m,n)\\in \\mathbb{Z}_{\\ge 0}\\times \\mathbb{N}$ there exists a place $\\mathfrak{p}$ of $K$ such that the point $\\alpha$ has preperiod $m$ and minimum period $n$ under the action of $\\varphi$. This answers a conjecture made by Ingram-Silverman and Faber-Granville. We prove a similar result, under suitable modification, also when $\\varphi$ has points where it is totally ramified. We give several applications of our result, such as showing that for any tuple $(c_1,\\dots , c_{d-1})\\in k^{n-1}$ and for almost all pairs $(m_i,n_i)\\in \\mathbb{Z}_{\\ge 0}\\times \\mathbb{N}$ for $i=1,\\dots, d-1$, there exists a polynomial $f\\in k[z]$ of degree $d$ in normal form such that for each $i=1,\\dots, d-1$, the point $c_i$ has preperiod $m_i$ and minimum period $n_i$ under the action of $f$.", "revisions": [ { "version": "v1", "updated": "2014-07-07T03:54:13.000Z" } ], "analyses": { "keywords": [ "preperiodic points", "rational maps", "minimum period", "normal form", "similar result" ], "publication": { "doi": "10.1017/S0305004115000274", "journal": "Mathematical Proceedings of the Cambridge Philosophical Society", "year": 2015, "month": "Jul", "volume": 159, "number": 1, "pages": 165 }, "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2015MPCPS.159..165G" } } }