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math.SP2022
A growth estimate for the monodromy matrix of a canonical system
Raphael Pruckner, Harald Woracek
We investigate the spectrum of 2-dimensional canonical systems in the limit circle case. It is discrete and, by the Krein-de Branges formula, cannot be more dense than the integers…
math.SP2019
Canonical systems with discrete spectrum
Roman Romanov, Harald Woracek
We study spectral properties of two-dimensional canonical systems , , where the Hamiltonian is locally integrable on , positive semidefinite…
math.SP2012
Spectral multiplicity of selfadjoint Schroedinger operators on star-graphs with standard interface conditions
Sergey Simonov, Harald Woracek
We analyze the singular spectrum of selfadjoint operators which arise from pasting a finite number of boundary relations with a standard interface condition. A model example for th…