New unlikely intersections on elliptic surfaces
Abstract
Consider a Jacobian elliptic surface with a section of infinite order. Previous work of the first author and Urz\'ua over the complex numbers gives a bound on the number of tangencies between and a torsion section of (an ``unlikely intersection''), and more precisely, an exact formula for the weighted number of tangencies between and elements of the ``Betti foliation''. This work used analytic techniques that apparently do not generalize to positive characteristic. In this paper, we extend their work to characteristic , and we develop a second approach to tangency properties of algebraic curves on a complex elliptic surface, yielding a new family of unlikely intersections with a strong connection to a famous homomorphism of Manin. We also correct inaccuracies in the literature about this homomorphism.
Cite
@article{arxiv.2508.06680,
title = {New unlikely intersections on elliptic surfaces},
author = {Douglas Ulmer and José Felipe Voloch},
journal= {arXiv preprint arXiv:2508.06680},
year = {2025}
}