|
In mathematics, an Artin–Schreier curve is a plane curve defined over an algebraically closed field of characteristic by an equation : for some rational function over that field. One of the most important examples of such curves is hyperelliptic curves in characteristic 2, whose Jacobian varieties have been suggested for use in cryptography. It is common to write these curves in the form : for some polynomials and . == Definition == More generally, an ''Artin-Schreier curve'' defined over an algebraically closed field of characteristic is a branched covering : of the projective line of degree . Such a cover is necessarily cyclic, that is, the Galois group of the corresponding algebraic function field extension is the cyclic group . In other words, is an Artin–Schreier extension. The fundamental theorem of Artin–Schreier theory implies that such a curve defined over a field has an affine model : for some rational function that is not equal for for any other rational function . In other words, if we define polynomial , then we require that . 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Artin–Schreier curve」の詳細全文を読む スポンサード リンク
|