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Bibliographic Details
Main Author: Emmel, Christian
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2407.07491
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Table of Contents:
  • Let S be a symmetric relation with deficiency index (1,1). In this article, we extend Krein`s resolvent formalism in order to describe all, not necessarily self-adjoint, extensions $S \subset \tilde{A}$ with $\varrho(\tilde{A})\neq \emptyset$. The corresponding $Q$-functions turn out to be quasi-Herglotz functions. We will use their structure to characterize the spectrum of such extensions. Finally, we also provide a model for such an extension on a reproducing kernel Hilbert space when $S$ is simple.