English

Arithmetic unlikely intersections in powers of the multiplicative group

Number Theory 2026-07-17 v1

Abstract

Inspired by work of Bugeaud-Corvaja-Zannier, we formulate a conjecture about unlikely intersections in powers of the multiplicative group over the ring of integers in a number field. Broadly speaking, if an intersection with a subgroup scheme is unlikely for dimension reasons, its ``size" should not be too big compared to the ``complexity" of the subgroup scheme. We first obtain some results on likely intersections that serve as a benchmark for the unlikely case and generalize work of Barroero-Capuano-M\'erai-Ostafe-Sha. We then show that our conjecture in dimension 11 follows from work of Corvaja-Zannier, we obtain some partial result in dimension 22, and we present some open problems that are special cases of the conjecture.

Cite

@article{arxiv.2607.15741,
  title  = {Arithmetic unlikely intersections in powers of the multiplicative group},
  author = {Francesco Campagna and Gabriel Andreas Dill and Robert Wilms},
  journal= {arXiv preprint arXiv:2607.15741},
  year   = {2026}
}

Comments

Appendix written in collaboration with Robert Wilms. The preprint consists of 31 pages and 2 figures