Nonvanishing of Second Coefficients of Hecke Polynomials on the Newspace

Fuente: arXiv
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Main Authors: Cason, William, Jim, Akash, Medlock, Charlie, Ross, Erick, Vilardi, Trevor, Xue, Hui
Format: Preprint
Published: 2024
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_version_ 1866910835256852480
author Cason, William
Jim, Akash
Medlock, Charlie
Ross, Erick
Vilardi, Trevor
Xue, Hui
author_facet Cason, William
Jim, Akash
Medlock, Charlie
Ross, Erick
Vilardi, Trevor
Xue, Hui
contents For $m \geq 1$, let $N \geq 1$ be coprime to $m$, $k \geq 2$, and $χ$ be a Dirichlet character modulo $N$ with $χ(-1)=(-1)^k$. Then let $T_m^{\text{new}}(N,k,χ)$ denote the restriction of the $m$-th Hecke operator to the space $S_k^{\text{new}}(Γ_0(N), χ)$. We demonstrate that for fixed $m$ and trivial character $χ$, the second coefficient of the characteristic polynomial of $T_m^{\text{new}}(N,k)$ vanishes for only finitely many pairs $(N,k)$, and we further determine the sign. To demonstrate our method, for $m=2,4$, we also compute all pairs $(N,k)$ for which the second coefficient vanishes. In the general character case, we also show that excluding an infinite family where $S_k^{\text{new}}(Γ_0(N), χ)$ is trivial, the second coefficient of the characteristic polynomial of $T_m^{\text{new}}(N,k,χ)$ vanishes for only finitely many triples $(N,k,χ)$.
format Preprint
id arxiv_https___arxiv_org_abs_2407_11694
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Nonvanishing of Second Coefficients of Hecke Polynomials on the Newspace
Cason, William
Jim, Akash
Medlock, Charlie
Ross, Erick
Vilardi, Trevor
Xue, Hui
Number Theory
11F25, 11F72, 11F11
For $m \geq 1$, let $N \geq 1$ be coprime to $m$, $k \geq 2$, and $χ$ be a Dirichlet character modulo $N$ with $χ(-1)=(-1)^k$. Then let $T_m^{\text{new}}(N,k,χ)$ denote the restriction of the $m$-th Hecke operator to the space $S_k^{\text{new}}(Γ_0(N), χ)$. We demonstrate that for fixed $m$ and trivial character $χ$, the second coefficient of the characteristic polynomial of $T_m^{\text{new}}(N,k)$ vanishes for only finitely many pairs $(N,k)$, and we further determine the sign. To demonstrate our method, for $m=2,4$, we also compute all pairs $(N,k)$ for which the second coefficient vanishes. In the general character case, we also show that excluding an infinite family where $S_k^{\text{new}}(Γ_0(N), χ)$ is trivial, the second coefficient of the characteristic polynomial of $T_m^{\text{new}}(N,k,χ)$ vanishes for only finitely many triples $(N,k,χ)$.
title Nonvanishing of Second Coefficients of Hecke Polynomials on the Newspace
topic Number Theory
11F25, 11F72, 11F11
url https://arxiv.org/abs/2407.11694