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A logarithmic structure theorem for multiplicative functions with small partial sums

Number Theory 2026-05-05 v1

Abstract

Let DND\in\mathbb{N}, let A>D+1A>D+1, and let Q3Q\geqslant3. Consider the class of multiplicative functions f:NCf:\mathbb{N}\to\mathbb{C} such that nxf(n)x(logQ)AD1/(logx)A|\sum_{n\leqslant x}f(n)|\le x(\log Q)^{A-D-1}/(\log x)^A for all xQx\geqslant Q, and such that ΛfDΛ|\Lambda_f|\leqslant D\Lambda, where Λf\Lambda_f is defined via the Dirichlet convolution identity flog=Λfff\log=\Lambda_f*f and Λ\Lambda denotes von Mangoldt's function. We prove there exist parameters m{0,1,,D}m\in\{0,1,\dots,D\} and Q=QDQD1Qm<Qm+1=Q=Q_D\leqslant Q_{D-1}\le \cdots\leqslant Q_m<Q_{m+1}=\infty such that pIRe(f(p)+j)/p=OA,D(1)\sum_{p\in I} \mathrm{Re}(f(p)+j)/p=O_{A,D}(1) for all j=m,m+1,,Dj=m,m+1,\dots,D and all compact intervals I[Qj+1,Qj)I\subset[Q_{j+1},Q_j). Moreover, when nxf(n)x11/logQ/(logx)D+1|\sum_{n\leqslant x}f(n)|\le x^{1-1/\log Q}/(\log x)^{D+1} for all xQx\geqslant Q, we relate the parameters mm and QjQ_j to the location of zeroes of the Dirichlet series n1f(n)/ns\sum_{n\geqslant1} f(n)/n^s in the ball B(1,1/logQ)B(1,1/\log Q). These results generalize work of the author when D=1D=1. Their proof builds on earlier work of the author with Soundararajan, and of Sachpazis.

Keywords

Cite

@article{arxiv.2605.01412,
  title  = {A logarithmic structure theorem for multiplicative functions with small partial sums},
  author = {Dimitris Koukoulopoulos},
  journal= {arXiv preprint arXiv:2605.01412},
  year   = {2026}
}

Comments

18 pages

R2 v1 2026-07-01T12:46:38.365Z