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Bibliographic Details
Main Author: Kling, Anthony
Format: Preprint
Published: 2023
Subjects:
Online Access:https://arxiv.org/abs/2310.18869
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author Kling, Anthony
author_facet Kling, Anthony
contents Let $N\geq3$ and $r\geq1$ be integers and $p\geq2$ be a prime such that $p\nmid N$. One can consider two different integral structures on the space of modular forms over $\mathbb{Q}$, one coming from arithmetic via $q$-expansions, the other coming from geometry via integral models of modular curves. Both structures are stable under the Hecke operators; furthermore, their quotient is finite torsion. Our goal is to investigate the exponent of the annihilator of the quotient. We will apply methods due to Brian Conrad to the situation of modular forms of even weight and level $Γ(Np^{r})$ over $\mathbb{Q}_{p}(ζ_{Np^{r}})$ to obtain an upper bound for the exponent. We also use Klein forms to construct explicit modular forms of level $p^{r}$ whenever $p^{r}>3$, allowing us to compute a lower bound which agrees with the upper bound. Hence we are able to compute the exponent precisely.
format Preprint
id arxiv_https___arxiv_org_abs_2310_18869
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Comparison of integral structures on the space of modular forms of full level N
Kling, Anthony
Number Theory
Let $N\geq3$ and $r\geq1$ be integers and $p\geq2$ be a prime such that $p\nmid N$. One can consider two different integral structures on the space of modular forms over $\mathbb{Q}$, one coming from arithmetic via $q$-expansions, the other coming from geometry via integral models of modular curves. Both structures are stable under the Hecke operators; furthermore, their quotient is finite torsion. Our goal is to investigate the exponent of the annihilator of the quotient. We will apply methods due to Brian Conrad to the situation of modular forms of even weight and level $Γ(Np^{r})$ over $\mathbb{Q}_{p}(ζ_{Np^{r}})$ to obtain an upper bound for the exponent. We also use Klein forms to construct explicit modular forms of level $p^{r}$ whenever $p^{r}>3$, allowing us to compute a lower bound which agrees with the upper bound. Hence we are able to compute the exponent precisely.
title Comparison of integral structures on the space of modular forms of full level N
topic Number Theory
url https://arxiv.org/abs/2310.18869