Title: Riesz bases of exponentials.
Abstract:
A Riesz basis of a Hilbert space is the "second best thing" after an orthonormal basis. Examine the space of square integrable functions over some given subset of the real line or of Euclidean space. For which sets does this space enjoy a Riesz basis composed only of exponential functions? This problem is interesting theoretically, with many connections to entire functions and quasi-crystals, and has some application in the sampling of band-limited signals. We will survey what is known. including some recent progress achieved with Shahaf Nitzan. All terms will be explained in the talk.