114 citations · 767 across the 136 of their papers we have counts for
6 papers · 1 filter
On Matrix-Valued Herglotz Functions
Fritz Gesztesy, Eduard Tsekanovskii
We provide a comprehensive analysis of matrix-valued Herglotz functions and illustrate their applications in the spectral theory of self-adjoint Hamiltonian systems including matri…
An Addendum to Krein's Formula
Fritz Gesztesy, Konstantin A. Makarov, Eduard Tsekanovskii
We provide additional results in connection with Krein's formula, which describes the resolvent difference of two self-adjoint extensions A_1 and A_2 of a densely defined closed sy…
An Alternative Approach to Algebro-Geometric Solutions of the AKNS Hierarchy
Fritz Gesztesy, Ratnam Ratnaseelan
We develop an alternative systematic approach to the AKNS hierarchy based on elementary algebraic methods. In particular, we recursively construct Lax pairs for the entire AKNS hie…
A combined sine-Gordon and modified Korteweg-de Vries hierarchy and its algebro-geometric solutions
Fritz Gesztesy, Helge Holden
We derive a zero-curvature formalism for a combined sine-Gordon (sG) and modified Korteweg-de Vries (mKdV) equation which yields a local sGmKdV hierarchy. In complete analogy to ot…
Algebro-Geometric Quasi-Periodic Finite-Gap Solutions of the Toda and Kac-van Moerbeke Hierarchies
W. Bulla, F. Gesztesy, H. Holden +1
Combining algebro-geometric methods and factorization techniques for finite difference expressions we provide a complete and self-contained treatment of all real-valued quasi-perio…
A Characterization of All Elliptic Solutions of the AKNS Hierarchy
Fritz Gesztesy, Rudi Weikard
An explicit characterization of all elliptic algebro-geometric solutions of the AKNS hierarchy is presented. Our approach is based on (an extension of) a classical theorem of Picar…