9 papers
Spectral characterizations of stable operator semigroups
Morgan Callewaert, Lenny Neyt, Jasson Vindas
We introduce the notion of local pseudofunction spectrum for the infinitesimal generator of a bounded -semigroup on a Banach…
A PeÅczyÅski-Vogt decomposition result for (PLS)-spaces and sequence space representations
Andreas Debrouwere, Lenny Neyt
We establish a PelczyÅski-Vogt decomposition result for (PLS)-type power series spaces of infinite type. By combining this result with the theory of Gabor frames, we obtain sequen…
Optimal decay of semi-uniformly stable operator semigroups with empty spectrum
Morgan Callewaert, Lenny Neyt, Jasson Vindas
We show that it is impossible to quantify the decay rate of a semi-uniformly stable operator semigroup based on sole knowledge of the spectrum of its infinitesimal generator. More…
Quantitative uncertainty principles for time-frequency Gaussian decay
Lenny Neyt, Joachim Toft, Jasson Vindas
For real symmetric positive definite matrices and , we characterize when a function satisfies \[ |f(x)| \lesssim e^{-(\frac12 - λ) \langle Ax, x\r…
Bornological LB-spaces and idempotent adjunctions
Jack Kelly, Lenny Neyt, Sven-Ake Wegner
The notion of an LB-space was introduced by Grothendieck in his 1953 thèse, referring to a countable colimit of Banach spaces taken within the category of locally convex topologic…
Weighted function spaces: convolutors, multipliers, and mollifiers
Lenny Neyt, Yoshihiro Sawano
We study smooth function spaces of Gelfand-Shilov type, with global behavior governed through a translation-invariant Banach function space and localized via a weight function syst…