Dear Colleagues and Students,
You are cordially invited to the Analysis Seminar organized by the Department of Mathematics.
Speaker: Sergey Favorov (Karazin’s Kharkiv University, Ukraine)
“A local version of Wiener’s theorem on absolutely convergent Fourier series”
Abstract: The well-known Wiener theorem states that if the function f is bounded away from zero on [0, 2π] and has an absolutely convergent Fourier series expansion, then the function 1 / f has the same property.
A local version of this theorem is proved without the condition of boundedness away from zero. It also extends to Dirichlet series.
Applications: 1) in the theory of quasicrystals (a new sufficient condition for the representability of a discrete measure support in Euclidean space as the union of a finite number of lattices)
2) a new sufficient condition for a discrete set in Euclidean space to be a set of coherent frequencies.
Date: Monday, November 11, 2019
Place: SA – Z18