Cusps in $\mathbb{C}^3$ with prescribed ramification
Algebraic Geometry
2023-10-18 v2 Combinatorics
Number Theory
Abstract
We study value semigroups associated to germs of maps with fixed ramification profiles in a distinguished point. We then apply our analysis to deduce that Severi varieties of unicuspidal rational fixed-degree curves with value semigroup in are often reducible when is either 1) the semigroup of a generic cusp whose ramification profile is a supersymmetric triple; or 2) a supersymmetric semigroup with ramification profile given by a supersymmetric triple. In doing so, we uncover new connections with additive combinatorics and number theory.
Cite
@article{arxiv.2303.09303,
title = {Cusps in $\mathbb{C}^3$ with prescribed ramification},
author = {Ethan Cotterill and Nathan Kaplan and Renata Vieira Costa},
journal= {arXiv preprint arXiv:2303.09303},
year = {2023}
}
Comments
Adjusted numerical hypotheses to reflect the fact that the degree should be at least the valuation of the conductor of the cusp, which in particular is true whenever $d \geq 2g$