On the p-rank of an abelian variety and its endomorphism algebra

• Autores: Josep González
• Localización: Publicacions matematiques, ISSN 0214-1493, Vol. 42, Nº 1, 1998, págs. 119-130
• Idioma: inglés
• Títulos paralelos:
  • El rango p de una variedad abeliana y su álgebra de endomorfismo
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• Resumen

  • Let $A$ be an abelian variety defined over a finite field. In this paper, we discuss the relationship between the $p$-rank of $A$, $r(A)$, and its endomorphism algebra, $\operatorname{End}^0(A)$. As is well known, $\operatorname{End}^0(A)$ determines $r(A)$ when $A$ is an elliptic curve. We show that, under some conditions, the value of $r(A)$ and the structure of $\operatorname{End}^0(A)$ are related. For example, if the center of $\operatorname{End}^0(A)$ is an abelian extension of $\Bbb Q$, then $A$ is ordinary if and only if $\operatorname{End}^0(A)$ is a commutative field. Nevertheless, we give an example in dimension 3 which shows that the algebra $\operatorname{End}^0(A)$ does not determine the value $r(A)$.