English

The stacky Batyrev-Manin conjecture and modular curves

Number Theory 2026-05-15 v3 Algebraic Geometry

Abstract

Let X0(N)\mathcal{X}_0(N) be the Deligne--Rapoport modular stack of elliptic curves endowed with a cyclic rational NN-isogeny over a number field FF. Let N{1,2,3,4,5,6,7,8,9,10,12,13,16,18,25},N\in\{1,2,3,4,5,6,7,8,9,10,12,13,16,18,25\}, which are precisely the values for which the coarse moduli space of X0(N)\mathcal{X}_0(N) is isomorphic to P1\mathbb{P}^1. We show that the stacky Batyrev--Manin conjecture [DY24] holds for the naive height on X0(N)\mathcal{X}_0(N) when F=QF=\mathbb{Q}. In the process, we give a concrete description of X0(N)\mathcal{X}_0(N) as a square root stack over a stacky curve.

Keywords

Cite

@article{arxiv.2602.19771,
  title  = {The stacky Batyrev-Manin conjecture and modular curves},
  author = {Ratko Darda and Changho Han},
  journal= {arXiv preprint arXiv:2602.19771},
  year   = {2026}
}

Comments

34 pages. v3: improved exposition (especially in the introduction)

R2 v1 2026-07-01T10:47:16.744Z