Zeros of the Zak transform of totally positive functions
This is a theoretical result for mathematicians studying time-frequency analysis and totally positive functions, but it is incremental as it extends known properties of Zak transforms to a specific class of functions.
The paper proves that the Zak transform of totally positive functions without a Gaussian factor in their Fourier transform has exactly one zero in its fundamental domain, using complex analysis and the connection to exponential B-splines.
We study the Zak transform of totally positive (TP) functions. We use the convergence of the Zak transform of TP functions of finite type to prove that the Zak transforms of all TP functions without Gaussian factor in the Fourier transform have only one zero in their fundamental domain of quasi-periodicity. Our proof is based on complex analysis, especially the Theorem of Hurwitz and some real analytic arguments, where we use the connection of TP functions of finite type and exponential B-splines.