On the exponential sum over squarefree integers
Abstract
Let μ be the Möbius function and e(t)=e2πit. We prove that if N≥2, α∈ℝ, (a,q)=1, and |α−a/q|≤ q−2, then |∑n≤ Nμ2(n)e(αn)|≪(N/q+q)(log 2N)5, with an absolute implied constant, and we deduce the corresponding estimate on the minor arcs of the Hardy--Littlewood dissection throughout the range Q≤ N1/2. The estimates of Schlage-Puchta [SP] and of Tolev [T] have the same dependence on q and Q but carry a factor Nε. The proof uses Heath-Brown's square sieve with sieving primes confined to an interval (P,2P], where P may be as small as a multiple of log N; a finite Fejér majorant in place of a truncated Fourier series; and, after completion of the character sums, a count of representations that exploits the restriction on the primes in place of the divisor function.
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BibTeX
@misc{robles2026exponential,
title = {{On the exponential sum over squarefree integers}},
author = {Nicolas Robles and Alexandru Zaharescu and Dirk Zeindler},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.03961},
eprint = {2609.03961},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.03961},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - On the exponential sum over squarefree integers
AU - Nicolas Robles
AU - Alexandru Zaharescu
AU - Dirk Zeindler
PY - 2026
DA - 2026/09/03
PB - arXiv
DO - 10.48550/arxiv.2609.03961
UR - https://arxiv.org/abs/2609.03961
AB - Let μ be the Möbius function and e(t)=e^2πit. We prove that if N≥2, α∈ℝ, (a,q)=1, and |α−a/q|≤ q^−2, then |∑_n≤ Nμ^2(n)e(αn)|≪(N/q+q)(log 2N)^5, with an absolute implied constant, and we deduce the corresponding estimate on the minor arcs of the Hardy--Littlewood dissection throughout the range Q≤ N^1/2. The estimates of Schlage-Puchta [SP] and of Tolev [T] have the same dependence on q and Q but carry a factor N^ε. The proof uses Heath-Brown's square sieve with sieving primes confined to an interval (P,2P], where P may be as small as a multiple of log N; a finite Fejér majorant in place of a truncated Fourier series; and, after completion of the character sums, a count of representations that exploits the restriction on the primes in place of the divisor function.
ER -