2026/03/31 by Seokhyun Choi · 1 citation
Mathematics · #math.NT #math.AG
We study the interaction between the group law on an abelian variety and the additive structure induced on its image under a morphism to projective space. Let A/F be a simple abelian variety, f:A → ℙn be a morphism which is finite onto its image, and Γ⊆ A(F) be a finite-rank subgroup. We show that for any affine chart \mathbbAn ⊆ ℙn and any finite subset X ⊆ f(Γ) ∩ \mathbbAn, the energy satisfies E(X) ≪ | X |2 and the sumset satisfies | X+X | ≫ | X |2. We also prove a product version of the main theorem, where the morphism is compatible with the decomposition of the abelian variety into simple factors. The proof uses the uniform Mordell-Lang conjecture proven by Gao--Ge--Kühne.