Analysis Seminar

In many settings orthonormal bases (ONB) are not easy to come
by. It is known, for example, that even the union of as few as two
intervals may not admit an ONB of exponentials. In cases where there are
no ONB, the next best option is a Riesz basis (i.e. the image of an ONB
under a bounded invertible operator). In this talk we will discuss the
following question: Does every finite union of intervals admit a Riesz
basis of exponentials? (Joint work with Gady Kozma).