Working Seminar on Banach and Metric Spaces
Spring 2024
Date: | February 8, 2024 |
Time: | 10:00am |
Location: | BLOC 302 |
Speaker: | Kostas Konstantos, York University |
Title: | Orthogonal Reduction to a Diagonal Operator (Part I) |
Date: | February 15, 2024 |
Time: | 10:00am |
Location: | BLOC 302 |
Speaker: | Kostas Konstantos, York University |
Title: | Orthogonal Reduction to a Diagonal Operator (part II) |
Date: | April 18, 2024 |
Time: | 10:00am |
Location: | BLOC 302 |
Speaker: | Hung Viet Chu, Texas A&M University |
Title: | The Radon-Nikodym property and curves with zero derivatives for nonlocally convex spaces (after Nigel Kalton) |
Date: | April 25, 2024 |
Time: | 10:00am |
Location: | BLOC 302 |
Speaker: | Hung Viet Chu, Texas A&M University |
Title: | The Radon-Nikodym property and curves with zero derivatives for nonlocally convex spaces II (after Nigel Kalton) |
Date: | April 29, 2024 |
Time: | 09:00am |
Location: | BLOC 140 |
Title: | STEaLTH Workshop on the Xp inequalities |
Date: | May 2, 2024 |
Time: | 10:00am |
Location: | BLOC 302 |
Speaker: | Cosmas Kravaris, Princeton University |
Title: | Lower bounds on the discrepancy of axis parallel rectangles on the plane |
Abstract: | In 1954, Roth proved that for any N points on the unit square [0,1]^2, there is a rectangle [0,q_1]x[0,q_2] inside [0,1]^2 such that the number of points it contains differs from q_1 q_2 N by at least the Ω(sqrt(log N)). Hence there is a limit to how well a finite set of points on the unit square can approximate the uniform measure. The bound was improved by Schmidt in 1972 to Ω(log N), which is known to be sharp. In this talk, we will prove these two results, by exploiting the structure of the Haar basis on the plane. The bound of Roth states that if we pick an axis parallel rectangle at random, then the discrepancy squared is bounded from below (e.g. an L^2 norm estimate on the discrepancy). If time permits, we discuss how this result generalizes to L^p moments using the Littlewood-Paley inequalities. |