8 citations · 46 across the 25 of their papers we have counts for
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Spectral Analysis of Darboux Transformations for the Focusing NLS Hierarchy
Radu C. Cascaval, Fritz Gesztesy, Helge Holden +1
We study Darboux transformations associated with the focusing nonlinear Schrödinger equation (NLS_-) and their effect on spectral properties of the underlying Lax operator. The lat…
Real-Valued Algebro-Geometric Solutions of the Camassa--Holm hierarchy
Fritz Gesztesy, Helge Holden
We provide a treatment of real-valued, smooth, and bounded algebro-geometric solutions of the Camassa--Holm (CH) hierarchy and describe the associated isospectral torus. We also di…
, Exponential Herglotz Representations, and Spectral Averaging
Fritz Gesztesy, Konstantin A. Makarov
We revisit the concept of spectral averaging and point out its origin in connection with one-parameter subgroups of and the corresponding Möbius transformations. In pa…
On Povzner--Wienholtz-type Self-Adjointness Results for Matrix-Valued Sturm--Liouville Operators
Steve Clark, Fritz Gesztesy
We derive Povzner--Wienholtz-type self-adjointness results for matrix-valued Sturm--Liouville operators $T=R^{-1}\big[-\f{d}{dx}P\f{d}{dx}+Q\big]$ in …
Matrix-Valued Generalizations of the Theorems of Borg and Hochstadt
E. D. Belokolos, F. Gesztesy, K. A. Makarov +1
We prove a generalization of the well-known theorems by Borg and Hochstadt for periodic self-adjoint Schrödinger operators without a spectral gap, respectively, one gap in their sp…