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Bibliographic Details
Main Authors: Ando, Chihiro, Harashita, Shushi
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2604.00822
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author Ando, Chihiro
Harashita, Shushi
author_facet Ando, Chihiro
Harashita, Shushi
contents For an elliptic curve $E$ over $\mathbb{Q}$ without complex multiplication, Lang and Trotter conjectured that the number of primes $p <X$ at which $E$ has a supersingular reduction is asymptotically equal to $c\sqrt{X}/\log X$, where $c>0$ is a constant depending only on $E$. While it remains an open question, an average estimation related to the Lang-Trotter conjecture was established by Fouvry and Murty. This result is called the Lang-Trotter conjecture on average. We extend the Lang-Trotter conjecture to curves of genus $2$ and obtain a similar result to the Lang-Trotter conjecture on average for the family of curves $C_λ:y^2=x(x-1)(x-λ)(x-(λ-1)/λ)(x-1/ (1-λ))$. These curves are characterized as curves of genus $2$ with reduced automorphism group containing symmetric group $S_3$.
format Preprint
id arxiv_https___arxiv_org_abs_2604_00822
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle The Lang-Trotter conjecture on average for genus-$2$ curves with $S_3$ reduced automorphism group
Ando, Chihiro
Harashita, Shushi
Number Theory
For an elliptic curve $E$ over $\mathbb{Q}$ without complex multiplication, Lang and Trotter conjectured that the number of primes $p <X$ at which $E$ has a supersingular reduction is asymptotically equal to $c\sqrt{X}/\log X$, where $c>0$ is a constant depending only on $E$. While it remains an open question, an average estimation related to the Lang-Trotter conjecture was established by Fouvry and Murty. This result is called the Lang-Trotter conjecture on average. We extend the Lang-Trotter conjecture to curves of genus $2$ and obtain a similar result to the Lang-Trotter conjecture on average for the family of curves $C_λ:y^2=x(x-1)(x-λ)(x-(λ-1)/λ)(x-1/ (1-λ))$. These curves are characterized as curves of genus $2$ with reduced automorphism group containing symmetric group $S_3$.
title The Lang-Trotter conjecture on average for genus-$2$ curves with $S_3$ reduced automorphism group
topic Number Theory
url https://arxiv.org/abs/2604.00822