Power residues on Abelian varieties

Abstract:

Given a prime l and an elliptic curve E defined over a number field k, we show that a non-zero point P∈E(k) lies in lE(k) if and only if P lies in lE(k)(mod ?) for almost all finite primes ? of k. We give conditions on l under which analogous results hold for Abelian varieties and with one point replaced by a finite number of points. We also construct examples to show that these conditions are essential.