The relative Manin–Mumford conjecture
- 1Department of Mathematics, UCLA, Los Angeles, 90095, CA, USA
- 2Department of Mathematics and Computer Science, University of Basel, Spiegelgasse 1, Basel, 4051, Switzerland
Abstract
We prove the Relative Manin–Mumford Conjecture for families of abelian varieties in characteristic 0. We follow the Pila–Zannier method to study special point problems, and we use the Betti map which goes back to work of Masser and Zannier in the case of curves. The key new ingredients compared to previous applications of this approach are a height inequality proved by both authors of the current paper and Dimitrov, and the first-named author’s study of certain degeneracy loci in subvarieties of abelian schemes. We also strengthen this result and prove a criterion for torsion points to be dense in a subvariety of an abelian scheme over ℂ. The Uniform Manin–Mumford Conjecture for curves embedded in their Jacobians was first proved by Kühne. We give a new proof, as a corollary to our main theorem, that does not use equidistribution.
Related
BibTeX
@article{gao2026relative,
title = {{The relative Manin–Mumford conjecture}},
author = {Ziyang Gao and Philipp Habegger},
journal = {Inventiones mathematicae},
year = {2026},
month = aug,
doi = {10.1007/s00222-026-01443-3},
url = {https://doi.org/10.1007/s00222-026-01443-3},
note = {CC BY},
}
RIS
TY - JOUR
TI - The relative Manin–Mumford conjecture
AU - Ziyang Gao
AU - Philipp Habegger
PY - 2026
DA - 2026/08/26
JO - Inventiones mathematicae
DO - 10.1007/s00222-026-01443-3
UR - https://doi.org/10.1007/s00222-026-01443-3
AB - We prove the Relative Manin–Mumford Conjecture for families of abelian varieties in characteristic 0. We follow the Pila–Zannier method to study special point problems, and we use the Betti map which goes back to work of Masser and Zannier in the case of curves. The key new ingredients compared to previous applications of this approach are a height inequality proved by both authors of the current paper and Dimitrov, and the first-named author’s study of certain degeneracy loci in subvarieties of abelian schemes. We also strengthen this result and prove a criterion for torsion points to be dense in a subvariety of an abelian scheme over ℂ. The Uniform Manin–Mumford Conjecture for curves embedded in their Jacobians was first proved by Kühne. We give a new proof, as a corollary to our main theorem, that does not use equidistribution.
SN - 0020-9910
SN - 1432-1297
ER -