English

On the conformal dimension of product measures

Classical Analysis and ODEs 2018-08-10 v2 Metric Geometry

Abstract

Given a compact set ERd1E \subset \mathbb{R}^{d - 1}, d1d \geq 1, write KE:=[0,1]×ERdK_{E} := [0,1] \times E \subset \mathbb{R}^{d}. A theorem of C. Bishop and J. Tyson states that any set of the form KEK_{E} is minimal for conformal dimension: if (X,d)(X,d) is a metric space and f ⁣:KE(X,d)f \colon K_{E} \to (X,d) is a quasisymmetric homeomorphism, then dimHf(KE)dimHKE.\dim_{\mathrm{H}} f(K_{E}) \geq \dim_{\mathrm{H}} K_{E}. We prove that the measure-theoretic analogue of the result is not true. For any d2d \geq 2 and 0s<d10 \leq s < d - 1, there exist compact sets ERd1E \subset \mathbb{R}^{d - 1} with 0<Hs(E)<0 < \mathcal{H}^{s}(E) < \infty such that the conformal dimension of ν\nu, the restriction of the (1+s)(1 + s)-dimensional Hausdorff measure on KEK_{E}, is zero. More precisely, for any ϵ>0\epsilon > 0, there exists a quasisymmetric embedding F ⁣:KERdF \colon K_{E} \to \mathbb{R}^{d} such that dimHFν<ϵ\dim_{\mathrm{H}} F_{\sharp}\nu < \epsilon.

Keywords

Cite

@article{arxiv.1704.07215,
  title  = {On the conformal dimension of product measures},
  author = {David Bate and Tuomas Orponen},
  journal= {arXiv preprint arXiv:1704.07215},
  year   = {2018}
}

Comments

27 pages. v2: incorporated minor referee comments. To appear in Proc. LMS