-elliptic sheaves and odd Jacobians
arXiv:1103.5833
Abstract
We examine the existence of rational divisors on modular curves of -elliptic sheaves and on Atkin-Lehner quotients of these curves over local fields. Using a criterion of Poonen and Stoll, we show that in infinitely many cases the Tate-Shafarevich groups of the Jacobians of these Atkin-Lehner quotients have non-square orders.
13 pages