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Main Authors: Ellenberg, Jordan, Shusterman, Mark
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2601.01242
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author Ellenberg, Jordan
Shusterman, Mark
author_facet Ellenberg, Jordan
Shusterman, Mark
contents For a finite group $G$ and a sufficiently large (but fixed) prime power $q$ coprime to $G$ we obtain asymptotics for the number of regular Galois extensions $L/ \mathbb{F}_q(t)$, with $\mathrm{Gal}(L/\mathbb{F}_q(t)) \cong G$, ramified at a single place of $\mathbb{F}_q(t)$, thus making progress on a positive characteristic analog of the Boston--Markin conjecture. We also obtain similar results for other arithmetic functions of the product of places of $\mathbb{F}_q(t)$ ramified in $L$, and for more general one-variable function fields over $\mathbb{F}_q$ in place of $\mathbb{F}_q(t)$. Some of our proofs make crucial use of a series of recent breakthroughs by Landesman--Levy, as well as a new `vanishing of stable homology in a given direction' result for representations of braid groups arising from braided vector spaces. Other inputs include a study of (rings of coinvariants of) braided vector spaces associated to racks with $2$-cocycles, a connection between convolution of arithmetic functions and direct sums of braided vector spaces, and a Goursat lemma for racks.
format Preprint
id arxiv_https___arxiv_org_abs_2601_01242
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Averages of Arithmetic Functions over Conductors of Function Fields
Ellenberg, Jordan
Shusterman, Mark
Number Theory
Algebraic Geometry
Algebraic Topology
Quantum Algebra
20F36 11G20 57K12 14F20
For a finite group $G$ and a sufficiently large (but fixed) prime power $q$ coprime to $G$ we obtain asymptotics for the number of regular Galois extensions $L/ \mathbb{F}_q(t)$, with $\mathrm{Gal}(L/\mathbb{F}_q(t)) \cong G$, ramified at a single place of $\mathbb{F}_q(t)$, thus making progress on a positive characteristic analog of the Boston--Markin conjecture. We also obtain similar results for other arithmetic functions of the product of places of $\mathbb{F}_q(t)$ ramified in $L$, and for more general one-variable function fields over $\mathbb{F}_q$ in place of $\mathbb{F}_q(t)$. Some of our proofs make crucial use of a series of recent breakthroughs by Landesman--Levy, as well as a new `vanishing of stable homology in a given direction' result for representations of braid groups arising from braided vector spaces. Other inputs include a study of (rings of coinvariants of) braided vector spaces associated to racks with $2$-cocycles, a connection between convolution of arithmetic functions and direct sums of braided vector spaces, and a Goursat lemma for racks.
title Averages of Arithmetic Functions over Conductors of Function Fields
topic Number Theory
Algebraic Geometry
Algebraic Topology
Quantum Algebra
20F36 11G20 57K12 14F20
url https://arxiv.org/abs/2601.01242