The Zak Transform on Gelfand–Shilov and Modulation Spaces with Applications to Operator Theory

Abstract

We characterize Gelfand–Shilov spaces, their distribution spaces and modulation spaces in terms of estimates of their Zak transforms. We use these results for general investigations of quasi-periodic functions and distributions. We also establish necessary and sufficient conditions for linear operators in order for these operators should be conjugations by Zak transforms.

An excursion to multiplications and convolutions on modulation spaces

“…and W(ω, ℓ p,q ), respectively, at each occurrence. (For r = ∞ , see [29] when p, q ∈ [1, ∞], [26,51] when p, q ∈ (0, ∞], and for r ∈ (0, ∞], see [54]. )…”

Step multipliers, Fourier step multipliers and multiplications on quasi-Banach modulation spaces

“…and W(ω, ℓ p,q ), respectively, at each occurrence. (For r = ∞ , see [14] when p, q ∈ [1, ∞], [11,29] when p, q ∈ (0, ∞], and for r ∈ (0, ∞], see [32]. )…”