- Analysis Seminar
- Wednesday, September 4, 2019 - 13:55 for 1 hour (actually 50 minutes)
- Skiles 005
- Mihalis Kolountzakis – University of Crete – email@example.com
Mathematicians have long been trying to understand which domains admit an orthogonal (or, sometimes, not) basis of exponentials of the form , for some set of frequencies (this is the spectrum of the domain). It is well known that we can do so for the cube, for instance (just take ), but can we find such a basis for the ball? The answer is no, if we demand orthogonality, but this problem is still open when, instead of orthogonality, we demand just a Riesz basis of exponentials.