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Main Authors: Dhanda, Kavita, Haynes, Alan, Prasala, Silmi
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2509.16890
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author Dhanda, Kavita
Haynes, Alan
Prasala, Silmi
author_facet Dhanda, Kavita
Haynes, Alan
Prasala, Silmi
contents Recent work by M. Afifurrahman established the first asymptotic estimates with error terms for the number of $2\times 2$ matrices with fixed non-zero determinant $n\in\mathbb{N}$, and with coefficients bounded in absolute value by $X$. In this paper we present a new proof of this result, which also gives an improved error term as $X\rightarrow\infty$. Similar to Afifurrahman's result, our error term is uniform in both $n$ and $X$, and our estimates are significant for $X$ as small as $n^{1/2+δ}$. To complement this, we also demonstrate that the exponent $1/2+δ$ in this statement cannot be reduced, by establishing a result which gives a different asymptotic main term when $n$ is either a prime or the square of a prime, and when $X=n^{1/2}$.
format Preprint
id arxiv_https___arxiv_org_abs_2509_16890
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Counting $2\times 2$ matrices with fixed determinant and bounded coefficients
Dhanda, Kavita
Haynes, Alan
Prasala, Silmi
Number Theory
11D04, 11D45, 11N45
Recent work by M. Afifurrahman established the first asymptotic estimates with error terms for the number of $2\times 2$ matrices with fixed non-zero determinant $n\in\mathbb{N}$, and with coefficients bounded in absolute value by $X$. In this paper we present a new proof of this result, which also gives an improved error term as $X\rightarrow\infty$. Similar to Afifurrahman's result, our error term is uniform in both $n$ and $X$, and our estimates are significant for $X$ as small as $n^{1/2+δ}$. To complement this, we also demonstrate that the exponent $1/2+δ$ in this statement cannot be reduced, by establishing a result which gives a different asymptotic main term when $n$ is either a prime or the square of a prime, and when $X=n^{1/2}$.
title Counting $2\times 2$ matrices with fixed determinant and bounded coefficients
topic Number Theory
11D04, 11D45, 11N45
url https://arxiv.org/abs/2509.16890