{ "id": "1006.2610", "version": "v2", "published": "2010-06-14T06:59:46.000Z", "updated": "2012-05-03T09:40:40.000Z", "title": "Functions which are PN on infiitely many extensions of Fp, p odd", "authors": [ "Elodie Leducq" ], "categories": [ "math.NT", "cs.IT", "math.IT" ], "abstract": "Let $p$ be an odd prime number. We prove that for $m\\equiv1\\mod p$, $x^m$ is perfectly nonlinear over $\\mathbb{F}_{p^n}$ for infinitely many $n$ if and only if $m$ is of the form $p^l+1$, $l\\in\\mathbb{N}$. First, we study singularities of $f(x,y)=\\frac{(x+1)^m-x^m-(y+1)^m+y^m}{x-y}$ and we use Bezout theorem to show that for $m\\neq 1+p^l$, $f(x,y)$ has an absolutely irreducible factor. Then by Weil theorem, f(x,y) has rationnal points such that $x\\neq y$ which means that $x^m$ is not PN.", "revisions": [ { "version": "v2", "updated": "2012-05-03T09:40:40.000Z" } ], "analyses": { "keywords": [ "extensions", "odd prime number", "rationnal points", "study singularities", "bezout theorem" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2010arXiv1006.2610L" } } }