English

On the absolute continuity of radial projections

Classical Analysis and ODEs 2017-09-15 v1 Metric Geometry

Abstract

Let d2d \geq 2 and d1<s<dd - 1 < s < d. Let μ\mu be a compactly supported Radon measure in Rd\mathbb{R}^{d} with finite ss-energy. I prove that the radial projections πxμ\pi_{x\sharp}\mu of μ\mu are absolutely continuous with respect to Hd1\mathcal{H}^{d - 1} for every centre xRdsptμx \in \mathbb{R}^{d} \setminus \operatorname{spt} \mu, outside an exceptional set of dimension at most 2(d1)s2(d - 1) - s. This is sharp. In fact, for xx outside an exceptional set as above, πxμLp(Sd1)\pi_{x\sharp}\mu \in L^{p}(S^{d - 1}) for some p>1p > 1.

Keywords

Cite

@article{arxiv.1709.04653,
  title  = {On the absolute continuity of radial projections},
  author = {Tuomas Orponen},
  journal= {arXiv preprint arXiv:1709.04653},
  year   = {2017}
}

Comments

6 pages. This paper supersedes arXiv:1602.07629