Browsing by Subject "resolvent"

Now showing 1 - 3 of 3

Access status: Open Access ,
A note on Hausdorff convergence of pseudospectra
(Wydawnictwa AGH, 2023) Lindner, Marko; Schmeckpeper, Dennis
For a bounded linear operator on a Banach space, we study approximation of the spectrum and pseudospectra in the Hausdorff distance. We give sufficient and necessary conditions in terms of pointwise convergence of appropriate spectral quantities.
Access status: Open Access ,
On some extensions of the A-model
(Wydawnictwa AGH, 2020) Juršėnas, Rytis
The A-model for finite rank singular perturbations of class $\mathfrak{H}_{-m-2}\setminus\mathfrak{H}_{-m-1}$, $m \in \mathbb{N}$, is considered from the perspective of boundary relations. Assuming further that the Hilbert spaces $(\mathfrak{H}_n)_{n\in\mathbb{Z}}$ admit an orthogonal decomposition $\mathfrak{H}^-_n \oplus \mathfrak{H}^+_n$, with the corresponding projections satisfying $P^{\pm}_{n+1}\subseteq P^{\pm}_n$, nontrivial extensions in the A-model are constructed for the symmetric restrictions in the subspaces.
Access status: Restricted ,
Zupełność układu wektorów własnych dla pewnej klasy operatorów różnicowych
(Data obrony: 2015-12-17) Chmura, Dominik
Wydział Matematyki Stosowanej