6 papers · 1 filter
Umbrella theorems for time-frequency representations
Paolo Boggiatto, Chiara Boiti, Alessandro Oliaro
An uncertainty principle due to H.S. Shapiro, the so-called Umbrella Theorem, asserts that there is no square integrable function uniformly dominating all the elements of an orthon…
Stability of global wave front sets by perturbations of frames
Chiara Boiti, David Jornet, Alessandro Oliaro
In this paper we consider the Gabor wave front set of ultradistributions in the frame of ultradifferentiable functions. We prove that such a wave front set, defined through a Gabor…
On the compactness of the Weyl operator in
Vicente Asensio, Chiara Boiti, David Jornet +1
We characterize, using time-frequency analysis, the continuity and compactness of the Weyl operator in global classes of ultradifferentiable functions , for weight f…
On the inclusion relations of global ultradifferentiable classes defined by weight matrices
Chiara Boiti, David Jornet, Alessandro Oliaro +1
We study and characterize the inclusion relations of global classes in the general weight matrix framework in terms of growth relations for the defining weight matrices. We conside…
Construction of the log-convex minorant of a sequence
Chiara Boiti, David Jornet, Alessandro Oliaro +1
We give a simple construction of the log-convex minorant of a sequence and consequently extend to the -dimensional case the well-known formula tha…
The Gabor wave front set in spaces of ultradifferentiable functions
Chiara Boiti, David Jornet, Alessandro Oliaro
Given a non-quasianalytic subadditive weight function we consider the weighted Schwartz space and the short-time Fourier transform on , $\mathcal…