English

Accessory Parameters for Four-Punctured Spheres

Number Theory 2022-03-29 v3 Classical Analysis and ODEs Complex Variables

Abstract

We study the accessory parameter problem for four-punctured spheres from the point of view of modular forms. The value of the accessory parameter giving the uniformization is characterized as the unique zero of a system of equations. This gives an effective method to compute the uniformizing differential equation. As an application, we compute numerically and study the local expansion of the real-analytic function associating to a four-punctured sphere the value of its uniformizing parameter, and make some observations on its coefficients.

Keywords

Cite

@article{arxiv.2004.02971,
  title  = {Accessory Parameters for Four-Punctured Spheres},
  author = {Gabriele Bogo},
  journal= {arXiv preprint arXiv:2004.02971},
  year   = {2022}
}
R2 v1 2026-06-23T14:41:49.583Z