{ "id": "1312.5108", "version": "v1", "published": "2013-12-18T12:16:08.000Z", "updated": "2013-12-18T12:16:08.000Z", "title": "Large $3$-groups of automorphisms of algebraic curves in characteristic $3$", "authors": [ "Massimo Giulietti", "Gabor Korchmaros" ], "categories": [ "math.AG" ], "abstract": "Let $S$ be a $p$-subgroup of the $\\K$-automorphism group $\\aut(\\cX)$ of an algebraic curve $\\cX$ of genus $\\gg\\ge 2$ and $p$-rank $\\gamma$ defined over an algebraically closed field $\\mathbb{K}$ of characteristic $p\\geq 3$.In this paper we prove that if $|S|>2(\\gg-1)$ then one of the following cases occurs. \\begin{itemize} \\item[(i)] $\\gamma=0$ and the extension $\\K(\\cX)/\\K(\\cX)^S$ completely ramifies at a unique place, and does not ramify elsewhere. \\item[(ii)] $\\gamma>0$, $p=3$, $\\cX$ is a general curve, $S$ attains the Nakajima's upper bound $3(\\gamma-1)$ and $\\K(\\cX)$ is an unramified Galois extension of the function field of a general curve of genus $2$ with equation $Y^2=cX^6+X^4+X^2+1$ where $c\\in\\K^*$. \\end{itemize} Case (i) was investigated by Stichtenoth, Lehr, Matignon, and Rocher.", "revisions": [ { "version": "v1", "updated": "2013-12-18T12:16:08.000Z" } ], "analyses": { "subjects": [ "14H37" ], "keywords": [ "algebraic curve", "characteristic", "general curve", "nakajimas upper bound", "function field" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2013arXiv1312.5108G" } } }