English

Badly approximable points on non-linear carpets

Number Theory 2026-03-13 v1 Dynamical Systems Metric Geometry

Abstract

The badly approximable points in Rd\mathbb{R}^d are those for which Dirichlet's approximation theorem cannot be improved by more than a constant, that is, they are the points most difficult to approximate by rational vectors. An important problem in Diophantine approximation is to determine when the set of badly approximable points intersects a given set in full dimension. We find the first class of non-linear non-conformal attractors for which this full intersection property holds, thus answering a question of Das-Fishman-Simmons-Urba\'nski from 2019. We also provide a formula for the Hausdorff dimension of these attractors which is of independent interest.

Keywords

Cite

@article{arxiv.2603.11822,
  title  = {Badly approximable points on non-linear carpets},
  author = {Roope Anttila and Jonathan M. Fraser and Henna Koivusalo},
  journal= {arXiv preprint arXiv:2603.11822},
  year   = {2026}
}

Comments

23 pages, 1 figure. Comments are appreciated!

R2 v1 2026-07-01T11:16:31.848Z