Pseudorandom Graphs for Logical Adversaries
Speaker: PrayaagTitle: Pseudorandom Graphs for Logical Adversaries
Date: 13 Feb 2023 16:30-18:00 EST
Location: SEC Level 3 NW Terrace
Food: Pizza
Given independent standard Gaussian points $v_1, \ldots, v_n$ in dimension $d$, for what values of $(n, d)$ does there exist with high probability an origin-symmetric ellipsoid that simultaneously passes through all of the points? This basic problem of fitting an ellipsoid to random points has connections to low-rank matrix decompositions, independent component analysis, and principal component analysis. Based on strong numerical evidence, it is conjectured that the ellipsoid fitting problem transitions from feasible to infeasible as the number of points $n$ increases, with a sharp threshold at $n \sim d^2/4$. In this talk, I will discuss recent progress on this conjecture based on joint work with Aaron Potechin, Paxton Turner and Alex Wein (https://arxiv.org/abs/2208.09493).