Browsing by Subject "symmetric operator"

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Access status: Restricted ,
Badanie operatora Schrödingera z PT-symetrycznym potencjałem
(Data obrony: 2014-07-10) Zakrzewski, Bartosz
Wydział Matematyki Stosowanej
Access status: Open Access ,
Functional models for Nevanlinna families
(2008) Behrndt, Jussi; Hassi, Seppo; Snoo, Henk de
The class of Nevanlinna families consists of $\mathbb{R}$-symmetric holomorphic multivalued functions on $\mathbb{C} \setminus \mathbb{R}$ with maximal dissipative (maximal accumulative) values on $\mathbb{C}_{+}$ ($\mathbb{C}_{-}$, respectively) and is a generalization of the class of operator-valued Nevanlinna functions. In this note Nevanlinna families are realized as Weyl families of boundary relations induced by multiplication operators with the independent variable in reproducing kernel Hilbert spaces.
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: Open Access ,
Operators in divergence form and their Friedrichs and Kreĭn extensions
(2011) Arlinskij, Ûrij Moiseevič; Kovalev, Ûrij
For a densely defined nonnegative symmetric operator $\mathcal{A} = L_2^*L_1$ in a Hilbert space, constructed from a pair $L_1 \subset L_2$ of closed operators, we give expressions for the Friedrichs and Kreĭn nonnegative selfadjoint extensions. Some conditions for the equality $(L_2^* L_1)^* = L_1^* L_2$ are obtained. Applications to 1D nonnegative Hamiltonians, corresponding to point interactions, are given
Access status: Restricted ,
Podstawowe własności operatorów symetrycznych i samosprzężonych. Nierówności dla operatorów samosprzężonych
(Data obrony: 2010-07-08) Kogut, Marcin
Wydział Matematyki Stosowanej
Access status: Restricted ,
Przestrzenie energetyczne laplasjanów na grafach
(Data obrony: 2016-06-30) Koutny, Kamila
Wydział Matematyki Stosowanej
Access status: Restricted ,
Rozszerzenia samosprzężone półograniczonych operatorów symetrycznych
(Data obrony: 2018-07-27) Kustra, Marcin
Wydział Matematyki Stosowanej