114 citations · 767 across the 136 of their papers we have counts for
156 papers
Some Remarks On Krein--von Neumann Extensions
Fritz Gesztesy, Selim Sukhtaiev
We survey various properties of Krein--von Neumann extensions and the reduced Krein--von Neumann operator $\hatt S_K$ in connection with a strictly positive (symmetric) opera…
Abstract Left-Definite Theory: A Model Operator Approach, Examples, Fractional Sobolev Spaces, and Interpolation Theory
Christoph Fischbacher, Fritz Gesztesy, Paul Hagelstein +1
We use a model operator approach and the spectral theorem for self-adjoint operators in a Hilbert space to derive the basic results of abstract left-definite theory in a straightfo…
Weak Coupling and Spectral Instability for Neumann Laplacians
Jussi Behrndt, Fritz Gesztesy, Henk de Snoo
We prove an abstract criterion on spectral instability of nonnegative selfadjoint extensions of a symmetric operator and apply this to self-adjoint Neumann Laplacians on bounded Li…
Essential self-adjointness of even-order, strongly singular, homogeneous half-line differential operators
Fritz Gesztesy, Markus Hunziker, Gerald Teschl
We consider essential self-adjointness on the space of even order, strongly singular, homogeneous differential operators associated with differential exp…
A Bessel Analog of the Riesz Composition Formula
Christoph Fischbacher, Fritz Gesztesy, Roger Nichols
We provide an elementary derivation of the Bessel analog of the celebrated Riesz composition formula and use the former to effortlessly derive the latter.
The Jacobi operator on and its various -functions
Fritz Gesztesy, Lance L. Littlejohn, Mateusz Piorkowski +1
We offer a detailed treatment of spectral and Weyl-Titchmarsh-Kodaira theory for all self-adjoint Jacobi operator realizations of the differential expression \begin{align*} τ_{α,β}…