English

Elliptic curves and finitely generated Galois groups

Number Theory 2025-10-02 v1

Abstract

Let KK be an extension of Q\mathbb{Q} and A/KA/K an elliptic curve. If Gal(Kˉ/K)\mathrm{Gal}(\bar K/K) is finitely generated, then AA is of infinite rank over KK. In particular, this implies the g=1g=1 case of the Junker-Koenigsmann conjecture. This "anti-Mordellic'' result follows from a new "Mordellic'' theorem, which asserts that if K0K_0 is finitely generated over Q\mathbb{Q}, the points of an abelian variety A0/K0A_0/K_0 over the compositum of all bounded-degree Galois extensions of K0K_0 form a virtually free abelian group. This, in turn, follows from a second Mordellic result, which asserts that the group of A0A_0 over the extension of K0K_0 defined by the torsion of A0(Kˉ0)A_0(\bar K_0) is free modulo torsion.

Keywords

Cite

@article{arxiv.2510.00750,
  title  = {Elliptic curves and finitely generated Galois groups},
  author = {Bo-Hae Im and Michael Larsen},
  journal= {arXiv preprint arXiv:2510.00750},
  year   = {2025}
}

Comments

16 pages

R2 v1 2026-07-01T06:10:15.662Z