{ "id": "1211.6044", "version": "v1", "published": "2012-11-23T01:25:49.000Z", "updated": "2012-11-23T01:25:49.000Z", "title": "Permutation polynomials of finite fields", "authors": [ "Christopher J. Shallue" ], "comment": "Honours thesis, Monash University", "categories": [ "math.NT", "math.CO" ], "abstract": "Let $\\mathbb{F}_q$ be the finite field of $q$ elements. Then a \\emph{permutation polynomial} (PP) of $\\mathbb{F}_q$ is a polynomial $f \\in \\mathbb{F}_q[x]$ such that the associated function $c \\mapsto f(c)$ is a permutation of the elements of $\\mathbb{F}_q$. In 1897 Dickson gave what he claimed to be a complete list of PPs of degree at most 6, however there have been suggestions recently that this classification might be incomplete. Unfortunately, Dickson's claim of a full characterisation is not easily verified because his published proof is difficult to follow. This is mainly due to antiquated terminology. In this project we present a full reconstruction of the classification of degree 6 PPs, which combined with a recent paper by Li \\emph{et al.} finally puts to rest the characterisation problem of PPs of degree up to 6. In addition, we give a survey of the major results on PPs since Dickson's 1897 paper. Particular emphasis is placed on the proof of the so-called \\emph{Carlitz Conjecture}, which states that if $q$ is odd and `large' and $n$ is even then there are no PPs of degree $n$. This important result was resolved in the affirmative by research spanning three decades. A generalisation of Carlitz's conjecture due to Mullen proposes that if $q$ is odd and `large' and $n$ is even then no polynomial of degree $n$ is `close' to being a PP. This has remained an unresolved problem in published literature. We provide a counterexample to Mullen's conjecture, and also point out how recent results imply a more general version of this statement (provided one increases what is meant by $q$ being `large').", "revisions": [ { "version": "v1", "updated": "2012-11-23T01:25:49.000Z" } ], "analyses": { "keywords": [ "finite field", "permutation polynomials", "conjecture", "dicksons claim", "full characterisation" ], "tags": [ "dissertation" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2012arXiv1211.6044S" } } }