English

Intersections of thick compact sets in $\mathbb{R}^d$

Classical Analysis and ODEs 2026-01-26 v3 Dynamical Systems

Abstract

We introduce a definition of thickness in Rd\mathbb{R}^d and obtain a lower bound for the Hausdorff dimension of the intersection of finitely or countably many thick compact sets using a variant of Schmidt's game. As an application we prove that given any compact set in Rd\mathbb{R}^d with thickness τ\tau, there is a number N(τ)N(\tau) such that the set contains a translate of all sufficiently small similar copies of every set in Rd\mathbb{R}^d with at most N(τ)N(\tau) elements; indeed the set of such translations has positive Hausdorff dimension. We also prove a gap lemma and bounds relating Hausdorff dimension and thickness.

Keywords

Cite

@article{arxiv.2102.01186,
  title  = {Intersections of thick compact sets in $\mathbb{R}^d$},
  author = {Kenneth Falconer and Alexia Yavicoli},
  journal= {arXiv preprint arXiv:2102.01186},
  year   = {2026}
}

Comments

We thank R Howat for pointing out a counterexample to Theorem 10 in the previous version. The proof fails because a combination of certain steps may lead to a degenerated case not excluded by the stated hypotheses. Under stronger assumptions one does not need to use those steps and the argument can be salvaged, see R Howats paper

R2 v1 2026-06-23T22:44:39.941Z