English

Cyclic covers of an algebraic curve from an adelic viewpoint

Algebraic Geometry 2026-03-16 v2 Rings and Algebras

Abstract

We propose an algebraic method for the classification of branched Galois covers of a curve XX focused on studying Galois ring extensions of its geometric adele ring \AX\A_{X}. As an application, we deal with cyclic covers; namely, we determine when a given cyclic ring extension of \AX\A_{X} comes from a corresponding cover of curves YXY \to X, which is reminiscent of a Grunwald-Wang problem, and also determine when two covers yield isomorphic ring extensions, which is known in the literature as an equivalence problem. This completely algebraic method permits us to recover ramification, certain analytic data such as rotation numbers, and enumeration formulas for covers.

Keywords

Cite

@article{arxiv.2501.04355,
  title  = {Cyclic covers of an algebraic curve from an adelic viewpoint},
  author = {Luis Manuel Navas Vicente and Francisco J. Plaza Martin},
  journal= {arXiv preprint arXiv:2501.04355},
  year   = {2026}
}

Comments

to appear in "CUBO, A Mathematical Journal", Vol. 28, No. 2 (2026)