3 papers
math.SP2026
The direct spectral problem for indefinite canonical systems
Matthias Langer, Harald Woracek
For indefinite (Pontryagin space) canonical systems that contain an inner singularity we prove the existence of generalised boundary values at the singularity, which are used to fo…
math.SP2025
Canonical systems whose Weyl coefficients have regularly varying asymptotics
Matthias Langer, Raphael Pruckner, Harald Woracek
For a two-dimensional canonical system on an interval with whose Hamiltonian is a.e.\ positive semidefinite, denote by its Weyl…
math.SP2024
Eigenvalue distribution of canonical systems: trace class and sparse spectrum
Matthias Langer, Jakob Reiffenstein, Harald Woracek
In this paper we consider two-dimensional canonical systems with discrete spectrum and study their eigenvalue densities. We develop a formula that determines the Stieltjes transfor…