English

On the distribution of sequences of the form $(q_ny)$

Number Theory 2024-11-20 v3

Abstract

We study the distribution of sequences of the form (qny)n=1(q_ny)_{n=1}^\infty, where (qn)n=1(q_n)_{n=1}^\infty is some increasing sequence of integers. In particular, we study the Lebesgue measure and find bounds on the Hausdorff dimension of the set of points γ[0,1)\gamma \in [0,1) which are well approximated by points in the sequence (qny)n=1(q_ny)_{n=1}^\infty. The bounds on Hausdorff dimension are valid for almost every yy in the support of a measure of positive Fourier dimension. When the required rate of approximation is very good or if our sequence is sufficiently rapidly growing, our dimension bounds are sharp. If the measure of positive Fourier dimension is itself Lebesgue measure, our measure bounds are also sharp for a very large class of sequences. We also give an application to inhomogeneous Littlewood type problems.

Keywords

Cite

@article{arxiv.2309.02893,
  title  = {On the distribution of sequences of the form $(q_ny)$},
  author = {S. Kristensen and T. Persson},
  journal= {arXiv preprint arXiv:2309.02893},
  year   = {2024}
}

Comments

15 pages. Niclas Technau pointed out to us that Theorems 1 and 2 in the original version were in fact consequences of arXiv:2307.14871 . In this revised version, we have strengthened both theorems to cover a wider class of sequences. A final version is revised in view of a referee's comments