The APDE seminar on Monday, 4/25, will be given by Hong Wang (UCLA) online via Zoom from 4:10pm to 5:00pm PST. To participate, email Sung-Jin Oh (sjoh@math.berkeley.edu).

Title: Distance sets spanned by sets of dimension d/2

Abstract: Suppose that E is a subset of $\mathbb{R}^{d}$, its distance set is defined as $\Delta(E):=\{ |x-y|, x, y \in E \}$.  Joint with Pablo Shmerkin, we prove that if the packing dimension and Hausdorff dimension of $E$ both equal to $d/2$, then $\dim_{H} \Delta(E) = 1$. 

We also prove that if $\dim_{H} E \geq d/2$, then $\dim_{H} \Delta(E) \geq d/2 + c_{d}$ when $d = 2, 3$; and $\underline{dim}_{B} \Delta(E) \geq d/2 + c_{d}$ when $d > 3$  for some explicit constants $c_{d}$.