39 citations · 169 across the 20 of their papers we have counts for
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Essential spectrum of systems of singular differential equations
Orif O. Ibrogimov, Heinz Langer, Matthias Langer +1
In this paper we develop a new method to determine the essential spectrum of coupled systems of singular differential equations. Applications to problems from magnetohydrodynamics…
Dichotomous Hamiltonians with Unbounded Entries and Solutions of Riccati Equations
Christiane Tretter, Christian Wyss
An operator Riccati equation from systems theory is considered in the case that all entries of the associated Hamiltonian are unbounded. Using a certain dichotomy property of the H…
Dirichlet-Neumann inverse spectral problem for a star graph of Stieltjes strings
Vyacheslav Pivovarchik, Natalia Rozhenko, Christiane Tretter
We solve two inverse spectral problems for star graphs of Stieltjes strings with Dirichlet and Neumann boundary conditions, respectively, at a selected vertex called root. The root…