{ "id": "2208.13281", "version": "v1", "published": "2022-08-28T20:14:32.000Z", "updated": "2022-08-28T20:14:32.000Z", "title": "Periodic points of rational functions of large degree over finite fields", "authors": [ "Derek Garton" ], "comment": "10 pages. arXiv admin note: text overlap with arXiv:2103.16533", "categories": [ "math.NT", "math.DS" ], "abstract": "For any $q$ a prime power, $j$ a positive integer, and $\\phi$ a rational function with coefficients in $\\mathbb{F}_{q^j}$, let $P_{q,j}(\\phi)$ be the proportion of $\\mathbb{P}^1(\\mathbb{F}_{q^j})$ that is periodic with respect to $\\phi$. Now suppose that $d$ is an integer greater than 1. We show that if $\\gcd{(d,q)}=1$, then as $j$ increases the expected value of $P_{q,j}(\\phi)$, as $\\phi$ ranges over rational functions of degree $d$, tends to 0. This theorem generalizes our previous work, which held only for polynomials, and only when $d=2$. To deduce this result, we prove a uniformity theorem on specializations of dynamical systems of rational functions with coefficients in certain finitely-generated algebras over residually finite Dedekind domains. This specialization theorem generalizes our previous work, which held only for algebras of dimension one.", "revisions": [ { "version": "v1", "updated": "2022-08-28T20:14:32.000Z" } ], "analyses": { "subjects": [ "37P05", "37P25", "37P35", "11T06", "13B05" ], "keywords": [ "rational function", "periodic points", "large degree", "finite fields", "specialization theorem generalizes" ], "note": { "typesetting": "TeX", "pages": 10, "language": "en", "license": "arXiv", "status": "editable" } } }