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Bibliographic Details
Main Authors: Chapman, Jonathan, Mudgal, Akshat
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2605.15434
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author Chapman, Jonathan
Mudgal, Akshat
author_facet Chapman, Jonathan
Mudgal, Akshat
contents Given $h, N \in \mathbb{N}$ satisfying $1 \leqslant h \leqslant N^2$, we prove an asymptotic formula for the number of solutions to the equation $x_1 x_2 - x_3 x_4 = h$ with $x_1, \ldots, x_4 \in [-N,N] \cap \mathbb{Z}$. We use a combination of combinatorial and analytic arguments in physical space along with bounds for Kloosterman sums. Our main result concerns the case when $h = N^2 + O(N)$, wherein we obtain square-root cancellation error terms by bypassing Kloosterman sum bounds and exploiting an additional symmetry available in this setting via Ramanujan sums. This confirms a speculation of Dhanda-Haynes-Prasala in a very general form.
format Preprint
id arxiv_https___arxiv_org_abs_2605_15434
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Counting solutions to the quadratic determinant equation
Chapman, Jonathan
Mudgal, Akshat
Number Theory
11D45, 11D09, 11N37
Given $h, N \in \mathbb{N}$ satisfying $1 \leqslant h \leqslant N^2$, we prove an asymptotic formula for the number of solutions to the equation $x_1 x_2 - x_3 x_4 = h$ with $x_1, \ldots, x_4 \in [-N,N] \cap \mathbb{Z}$. We use a combination of combinatorial and analytic arguments in physical space along with bounds for Kloosterman sums. Our main result concerns the case when $h = N^2 + O(N)$, wherein we obtain square-root cancellation error terms by bypassing Kloosterman sum bounds and exploiting an additional symmetry available in this setting via Ramanujan sums. This confirms a speculation of Dhanda-Haynes-Prasala in a very general form.
title Counting solutions to the quadratic determinant equation
topic Number Theory
11D45, 11D09, 11N37
url https://arxiv.org/abs/2605.15434