English

Improved bounds for restricted projection families via weighted Fourier restriction

Classical Analysis and ODEs 2022-12-14 v5 Analysis of PDEs

Abstract

It is shown that if AR3A \subseteq \mathbb{R}^3 is a Borel set of Hausdorff dimension dimA(3/2,5/2)\dim A \in (3/2,5/2), then for a.e. θ[0,2π)\theta \in [0,2\pi) the projection πθ(A)\pi_{\theta}(A) of AA onto the 2-dimensional plane orthogonal to 12(cosθ,sinθ,1)\frac{1}{\sqrt{2}}(\cos \theta, \sin \theta, 1) satisfies dimπθ(A)max{4dimA9+56,2dimA+13}\dim \pi_{\theta}(A) \geq \max\left\{\frac{4\dim A}{9} + \frac{5}{6},\frac{2\dim A+1}{3} \right\}. This improves the bound of Oberlin and Oberlin, and of Orponen and Venieri, for dimA(3/2,5/2)\dim A \in (3/2,5/2). More generally, a weaker lower bound is given for families of planes in R3\mathbb{R}^3 parametrised by curves in S2S^2 with nonvanishing geodesic curvature.

Keywords

Cite

@article{arxiv.1911.00615,
  title  = {Improved bounds for restricted projection families via weighted Fourier restriction},
  author = {Terence L. J. Harris},
  journal= {arXiv preprint arXiv:1911.00615},
  year   = {2022}
}

Comments

50 pages, 1 figure. Accepted version