A1 Refereed original research article in a scientific journal
An L2-BOUND FOR THE BARBAN–VEHOV WEIGHTS
Authors: Ramaré, Olivier; Zuniga-Alterman, Sebastian
Publisher: Adam Mickiewicz University (Euclid)
Publication year: 2026
Journal: Functiones Et Approximatio: Commentarii Mathematici
Volume: 74
Issue: 1
First page : 74
Last page: 80
ISSN: 0208-6573
eISSN: 2080-9433
DOI: https://doi.org/10.7169/facm/241018-19-5
Publication's open availability at the time of reporting: No Open Access
Publication channel's open availability : Delayed Open Access publication channel (the publications become open after an embargo period)
Web address : https://doi.org/10.7169/facm/241018-19-5
Let λ be the Barban–Vehov weights, defined in (1). Let X ≥ z₁ ≥ 100 and z₂ = z₁². We prove that
∑{n ≤ X} (1/n) (∑{d | n} λ_d)² ≤ 30 · (log X) / log(z₂ / z₁),
saving more than a factor of 5 on what was the best known constant in such an inequality. Two related estimates are also provided for X ≥ z₁ ≥ 100 and z₂ = z₁^τ for some τ > 1.
Funding information in the publication:
The second author has been supported by the Finnish Centre of Excellence in Randomness and Structures grant 346307 of the Academy of Finland