114 citations · 767 across the 136 of their papers we have counts for
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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}…
Strict domain monotonicity of the principal eigenvalue and a characterization of lower boundedness for the Friedrichs extension of four-coefficient Sturm-Liouville operators
Fritz Gesztesy, Roger Nichols
Using the variational characterization of the principal (i.e., smallest) eigenvalue below the essential spectrum of a lower semibounded self-adjoint operator, we prove strict domai…
The Jacobi operator and its Donoghue -functions
Fritz Gesztesy, Mateusz Piorkowski, Jonathan Stanfill
In this paper we construct Donoghue -functions for the Jacobi differential operator in , associated to the differential expression \begi…
On domain properties of Bessel-type operators
Fritz Gesztesy, Michael M. H. Pang, Jonathan Stanfill
Motivated by a recent study of Bessel operators in connection with a refinement of Hardy's inequality involving on the finite interval , we now take a closer l…
On essential self-adjointness of singular Sturm-Liouville operators
S. Blake Allan, Fritz Gesztesy, Alexander Sakhnovich
Considering singular Sturm--Liouville differential expressions of the type \[ τ_α = -(d/dx)x^α(d/dx) + q(x), \quad x \in (0,b), \; α\in \mathbb{R}, \] we employ some Sturm comparis…