University of Illinois Urbana-Champaign

Restricted projection families and weighted Fourier restriction

Harris, Terence L. J.

Content Files
HARRIS-DISSERTATION-2020.pdf

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https://hdl.handle.net/2142/107893

Description

Title
Restricted projection families and weighted Fourier restriction
Author(s)
Harris, Terence L. J.
Issue Date
2020-04-21
Director of Research (if dissertation) or Advisor (if thesis)
Erdoğan, Burak
Doctoral Committee Chair(s)
Tzirakis, Nikolaos
Committee Member(s)
  • Li, Xiaochun
  • Albin, Pierre
Department of Study
Mathematics
Discipline
Mathematics
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Date of Ingest
2020-08-26T21:54:21Z
Keyword(s)
  • Hausdorff dimension
  • Orthogonal projections
Abstract
In the first part of this thesis, it is shown that if $A \subseteq \mathbb{R}^3$ is a Borel set of Hausdorff dimension $\dim A > 3/2$, then for a.e.~$\theta \in [0,2\pi)$ the projection $\pi_{\theta}(A)$ of $A$ onto the 2-dimensional plane orthogonal to $\frac{1}{\sqrt{2}}(\cos \theta, \sin \theta, 1)$ satisfies \[ \dim \pi_{\theta}(A) \geq \min\left\{\frac{4\dim A}{9} + \frac{5}{6},2 \right\}. \] This improves the bound of Oberlin and Oberlin \cite{oberlin}, and of Orponen and Venieri \cite{venieri}, for $\dim A \in (1.5,2.4)$. In the second part, an improved lower bound is given for the decay of conical averages of Fourier transforms of measures, for cones of dimension $d \geq 4$. The proof uses a weighted version of the broad restriction inequality, a narrow decoupling inequality for the cone, and some techniques of Du and Zhang \cite{zhang} originally developed for the Schrödinger equation. Most of the work in this thesis was published by the author in different forms in \cite{THarris1} and \cite{THarris3}.
Graduation Semester
2020-05
Type of Resource
Thesis
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http://hdl.handle.net/2142/107893
Copyright and License Information
Copyright 2020 Terence Harris

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