English

A cluster criterion for potential degeneracy of superelliptic curves

Algebraic Geometry 2025-08-25 v1 Number Theory

Abstract

Let KK be a field with a discrete valuation; let pp be a prime; and let CC be the curve defined by an equation of the form yp=f(x)y^p = f(x). We show that the curve CC has a model over an algebraic extension of KK whose special fiber consists of genus-00 components and has at worst nodal singularities if and only if the cluster data of the roots of ff satisfies a certain criterion, and when these hold, we show explicitly how to build the minimal regular model of CC. We develop an interpretation of cluster data in terms of a convex hull in the Berkovich projective line and express the above results directly in terms of this convex hull.

Keywords

Cite

@article{arxiv.2508.15974,
  title  = {A cluster criterion for potential degeneracy of superelliptic curves},
  author = {Jeffrey Yelton},
  journal= {arXiv preprint arXiv:2508.15974},
  year   = {2025}
}

Comments

48 pages; 7 sections with an appendix; 5 figures; feedback welcome!