English

Dimensions of projected sets and measures on typical self-affine sets

Dynamical Systems 2023-07-21 v2 Classical Analysis and ODEs

Abstract

Let T1,,TmT_1,\ldots, T_m be a family of d×dd\times d invertible real matrices with Ti<1/2\|T_i\|<1/2 for 1im1\leq i\leq m. For a=(a1,,am)Rmd{\bf a}=(a_1,\ldots, a_m)\in \Bbb R^{md}, let πa:  Σ={1,,m}NRd\pi^{{\bf a}}:\; \Sigma=\{1,\ldots, m\}^{\Bbb N}\to \Bbb R^d denote the coding map associated with the affine IFS {Tix+ai}i=1m\{T_ix+a_i\}_{i=1}^m. We show that for every Borel probability measure μ\mu on Σ\Sigma, each of the following dimensions (lower and upper Hausdorff dimensions, lower and upper packing dimensions) of πaμ\pi^{\bf a}_*\mu is constant for Lmd\mathcal L^{md}-a.e.~aRmd{\bf a}\in \Bbb R^{md}, where πaμ\pi^{\bf a}_*\mu stands for the push-forward of μ\mu by πa\pi^{\bf a}. In particular, we give a necessary and sufficient condition on μ\mu so that πaμ\pi^{\bf a}_*\mu is exact dimensional for Lmd\mathcal L^{md}-a.e.~aRmd{\bf a}\in \Bbb R^{md}. Moreover, for every analytic set EΣE\subset \Sigma, each of the Hausdorff, packing, lower and upper box-counting dimensions of πa(E)\pi^{{\bf a}}(E) is constant for Lmd\mathcal L^{md}-a.e.~aRmd{\bf a}\in \Bbb R^{md}. Formal dimension formulas of these projected measures and sets are given. The Hausdorff dimensions of exceptional sets are estimated.

Keywords

Cite

@article{arxiv.2209.00228,
  title  = {Dimensions of projected sets and measures on typical self-affine sets},
  author = {De-Jun Feng and Chiu-Hong Lo and Cai-Yun Ma},
  journal= {arXiv preprint arXiv:2209.00228},
  year   = {2023}
}

Comments

Minor changes. To appear in Adv. Math