A note on limsup sets of annuli
Abstract
We consider the set of points in infinitely many max-norm annuli centred at rational points in . We give Jarn\'ik-Besicovitch type theorems for this set in terms of Hausdorff dimension. Interestingly, we find that if the outer radii are decreasing sufficiently slowly, dependent only on the dimension , and the thickness of the annuli is decreasing rapidly then the dimension of the set tends towards . We also consider various other forms of annuli including rectangular annuli and quasi-annuli described by the difference between balls of two different norms. Our results are deduced through a novel combination of a version of Cassel's Scaling Lemma and a generalisation of the Mass Transference Principle, namely the Mass transference principle from rectangles to rectangles due to Wang and Wu (Math. Ann. 2021).
Cite
@article{arxiv.2502.09807,
title = {A note on limsup sets of annuli},
author = {Mumtaz Hussain and Benjamin Ward},
journal= {arXiv preprint arXiv:2502.09807},
year = {2025}
}
Comments
12 pages