Halász theorems for Gaussian ideals in sectors and short intervals

Fuente: arXiv
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Main Author: Kuś, Jan
Format: Preprint
Published: 2026
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author Kuś, Jan
author_facet Kuś, Jan
contents We prove a quantitative Halász theorem for multiplicative functions on the nonzero ideals of $\mathbb{Z}[i]$, with bounds controlled by pretentious distance to the Archimedean characters $N^{it}$. We also prove a sectorial analogue: under angular non-pretentiousness, the sum of $f$ over ideals lying in a fixed sector is asymptotically given by the expected proportion of the unrestricted sum. Finally, under angular non-pretentiousness and a non-degeneracy condition on conjugate prime pairs, we prove a sectorial short-interval version of the Halász theorem for annular sectors whose radial thickness tends to infinity. The proof of the sectorial short-interval Halász theorem uses angular Fourier expansion, norm-compression to multiplicative functions on $\mathbb{N}$, and a theorem of Mangerel.
format Preprint
id arxiv_https___arxiv_org_abs_2605_19105
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Halász theorems for Gaussian ideals in sectors and short intervals
Kuś, Jan
Number Theory
11N37 (Primary), 11N60, 11R11 (Secondary)
We prove a quantitative Halász theorem for multiplicative functions on the nonzero ideals of $\mathbb{Z}[i]$, with bounds controlled by pretentious distance to the Archimedean characters $N^{it}$. We also prove a sectorial analogue: under angular non-pretentiousness, the sum of $f$ over ideals lying in a fixed sector is asymptotically given by the expected proportion of the unrestricted sum. Finally, under angular non-pretentiousness and a non-degeneracy condition on conjugate prime pairs, we prove a sectorial short-interval version of the Halász theorem for annular sectors whose radial thickness tends to infinity. The proof of the sectorial short-interval Halász theorem uses angular Fourier expansion, norm-compression to multiplicative functions on $\mathbb{N}$, and a theorem of Mangerel.
title Halász theorems for Gaussian ideals in sectors and short intervals
topic Number Theory
11N37 (Primary), 11N60, 11R11 (Secondary)
url https://arxiv.org/abs/2605.19105