Classi di isomorfismo delle cubiche diF q

LetF _q (q=p^r) be a field of characteristicp>3 andA the set of all elliptic cubic curves overF _q having a given absolute invariantj. Furthermore let ≈be the following equivalence relation: « if and only if and F_q are isomorphic overF _q as abelian varieties». The aim of this paper is to study the equivalence classes inA, induced by ≈, and the Frobenius' traces of the cubic curves belonging to different subclasses ofA.