Group Structure of Abelian Varieties

Abstract

Let $A$ be an abelian variety over $\mathbb{F}_q$. Let $h_A(t)$ be the characteristic polynomial of $A$. Rybakov showed that if $h_A(t)$ is squarefree and $G$ is any finite group with $|G| = h_A(1)$, then $G = A'(\mathbb{F}_q)$ for some $A'$ isogenous to $A$ if and only if the $\ell^{th}$ Hodge polygon of $G$ is under the $\ell^{th}$ Newton polygon of $h_A(1-t)$ for all primes $\ell$. In this paper, we will extend this result to get a classification theorem for the group structure of all abelian varieties.