Reductions of points on algebraic groups, II
Number Theory
2021-07-01 v1
Abstract
Let be the product of an abelian variety and a torus over a number field , and let be a positive integer. If is a point of infinite order, we consider the set of primes of such that the reduction is well defined and has order coprime to . This set admits a natural density, which we are able to express as a finite sum of products of -adic integrals, where varies in the set of prime divisors of . We deduce that the density is a rational number, whose denominator is bounded (up to powers of ) in a very strong sense. This extends the results of the paper "Reductions of points on algebraic groups" by Davide Lombardo and the second author, where the case prime is established.
Cite
@article{arxiv.1802.08527,
title = {Reductions of points on algebraic groups, II},
author = {Peter Bruin and Antonella Perucca},
journal= {arXiv preprint arXiv:1802.08527},
year = {2021}
}