Conductor-Discriminant Inequality for Tamely Ramified Cyclic Covers I
Abstract
We prove conductor-discriminant inequalities for all β€/n-covers of β1 defined over discretely valued fields K with excellent valuation ring πͺK and perfect residue field of characteristic not dividing n, modulo some calculations appearing in work of the third author (arXiv:2609.20585). Specifically, when such a curve X is given by yn = f(x) with f(x) βπͺK[x] and n|deg(f), and if π³ is its minimal regular model over πͺK, then the negative of the Artin conductor of π³ is bounded above by (nβ1)vK(disc(rad(f))). This is a direct generalization of previous work of the first two authors on hyperelliptic curves, which in turn generalized work of Ogg, Saito, Liu, and the second author. When f is monic, this strengthens a result of Kohls stating that the conductor exponent of the Jacobian of such a curve is bounded above by (nβ1)vK(disc(rad(f))).
Related
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- The Five-Point Case of Mordell's Discriminant Inequality
- Circular Rearrangement Inequality and Optimal Cyclic Birth and Death Chains
- The Strong Naor--Schechtman Convolution Inequality on the Product of Cyclic Groups
- Brauer-Kuroda relations for ramified graph covers
BibTeX
@misc{obus2026conductordiscriminant,
title = {{Conductor-Discriminant Inequality for Tamely Ramified Cyclic Covers I}},
author = {Andrew Obus and Padmavathi Srinivasan and Connor Stewart},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.20553},
eprint = {2609.20553},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.20553},
}
RIS
TY - UNPB
TI - Conductor-Discriminant Inequality for Tamely Ramified Cyclic Covers I
AU - Andrew Obus
AU - Padmavathi Srinivasan
AU - Connor Stewart
PY - 2026
DA - 2026/09/18
PB - arXiv
DO - 10.48550/arxiv.2609.20553
UR - https://arxiv.org/abs/2609.20553
AB - We prove conductor-discriminant inequalities for all β€/n-covers of β^1 defined over discretely valued fields K with excellent valuation ring πͺ_K and perfect residue field of characteristic not dividing n, modulo some calculations appearing in work of the third author (arXiv:2609.20585). Specifically, when such a curve X is given by y^n = f(x) with f(x) βπͺ_K[x] and n|deg(f), and if π³ is its minimal regular model over πͺ_K, then the negative of the Artin conductor of π³ is bounded above by (nβ1)v_K(disc(rad(f))). This is a direct generalization of previous work of the first two authors on hyperelliptic curves, which in turn generalized work of Ogg, Saito, Liu, and the second author. When f is monic, this strengthens a result of Kohls stating that the conductor exponent of the Jacobian of such a curve is bounded above by (nβ1)v_K(disc(rad(f))).
ER -