English

Sur la Structure de A-module de Drinfeld de rang 2

Algebraic Geometry 2007-05-23 v1

Abstract

Φ\Phi be a Drinfeld F_q[T]\mathbf{F}\_{q}[T]-module of rank 2, over a finite field LL. Let P_Φ(X)=P\_{\Phi}(X)= X2cX+μPmX^{2}-cX+\mu P^{m} (cc an element of F_q[T],\mathbf{F}\_{q}[T], μ\mu be a non-vanishing element of % \mathbf{F}\_{q}, mm the degree of the extension LL over the field % \mathbf{F}\_{q}[T]/P, and PP the F_q[T]\mathbf{F}\_{q}[T]-characteristic of % L and dd the degree of the polynomial PP) the characteristic polynomial of the Frobenius FF of LL. We will be interested in the structure of finite F_q[T]\mathbf{F}\_{q}[T]-module LΦL^{\Phi} induced by Φ\Phi over LL. Our main result is analogue to that of Deuring (see \cite{Deuring}) for elliptic curves : Let M=\frac{\mathbf{F}\_{q}[T]}{I\_{1}}\oplus \frac{\mathbf{F}\_{q}[T]}{% I\_{2}}, where I_1=(i_1)I\_{1}=(i\_{1}),I_2=(i_2) I\_{2}=(i\_{2}) (i_1i\_{1}, i_2i\_{2} being two polynomials of F_q[T]\mathbf{F}\_{q}[T]) such that : i_2(c2)i\_{2}\mid (c-2). Then there exists an ordinary Drinfeld F_q[T]\mathbf{F}\_{q}[T]-module Φ\Phi over LL of rank 2 such that : LΦL^{\Phi} M\simeq M. To cite this article: Mohamed-Saadbouh Mohamed-Ahmed, C. R. Acad. Sci. Paris, Ser. I ... (...).

Keywords

Cite

@article{arxiv.math/0606417,
  title  = {Sur la Structure de A-module de Drinfeld de rang 2},
  author = {Mohamed Saadbouh Mohamed Ahmed},
  journal= {arXiv preprint arXiv:math/0606417},
  year   = {2007}
}