English

Abelian geometric fundamental groups for curves over a $p$-adic field

Number Theory 2022-01-19 v1

Abstract

For a curve XX over a pp-adic field kk, using the class field theory of XX due to S. Bloch and S. Saito we study the abelian geometric fundamental group π1ab(X)geo\pi_1^{\mathrm{ab}}(X)^{\mathrm{geo}} of XX. In particular, it is investigated a subgroup of π1ab(X)geo\pi_1^{\mathrm{ab}}(X)^{\mathrm{geo}} which classifies the geometric and abelian coverings of XX which allow possible ramification over the special fiber of the model of XX. Under the assumptions that XX has a kk-rational point, XX has good reduction and its Jacobian variety has good ordinary reduction, we give some upper and lower bounds of this subgroup of π1ab(X)geo\pi_1^{\mathrm{ab}}(X)^{\mathrm{geo}}.

Keywords

Cite

@article{arxiv.2201.05982,
  title  = {Abelian geometric fundamental groups for curves over a $p$-adic field},
  author = {Evangelia Gazaki and Toshiro Hiranouchi},
  journal= {arXiv preprint arXiv:2201.05982},
  year   = {2022}
}
R2 v1 2026-06-24T08:51:24.188Z