H. Woracek

activity

20092026

most citedTermination in Convex Sets of Distributions

7 citations · 17 across the 19 of their papers we have counts for

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9 papers · 1 filter

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…

math.SP2022

Spectral multiplicity of selfadjoint Schroedinger operators on star-graphs with general interface conditions

Sergey Simonov, Harald Woracek

We consider selfadjoint operators obtained by pasting a finite number of boundary relations with one-dimensional boundary space. A typical example of such an operator is the Schröd…

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.SP2022★ 2 cited

Canonical systems whose Weyl coefficients have regularly varying asymptotics

Matthias Langer, Raphael Pruckner, Harald Woracek

For a two-dimensional canonical system $y^{'} (t) = z J H (t) y (t)$ on an interval $(0, L)$ with $0 < L \leq \infty$ whose Hamiltonian $H$ is a.e.\ positive semidefinite, denote by $q_{H}$ its Weyl…

math.SP2021

Canonical systems whose Weyl coefficients have dominating real part

Matthias Langer, Raphael Pruckner, Harald Woracek

For a two-dimensional canonical system $y^{'} (t) = z J H (t) y (t)$ on the half-line $(0, \infty)$ whose Hamiltonian $H$ is a.e. positive semi-definite, denote by $q_{H}$ its Weyl coefficient.…

math.SP2019

Canonical systems with discrete spectrum

Roman Romanov, Harald Woracek

We study spectral properties of two-dimensional canonical systems $y^{'} (t) = z J H (t) y (t)$ , $t \in [a, b)$ , where the Hamiltonian $H$ is locally integrable on $[a, b)$ , positive semidefinite…

math.SP2015

Bounds on order of indeterminate moment sequences

Raphael Pruckner, Roman Romanov, Harald Woracek

We investigate the order $ρ$ of the four entire functions in the Nevanlinna matrix of an indeterminate Hamburger moment sequence. We give an upper estimate for $ρ$ which is explici…

math.SP2015★ 7 cited

Direct and inverse spectral theorems for a class of canonical systems with two singular endpoints

Matthias Langer, Harald Woracek

Part I of this paper deals with two-dimensional canonical systems $y^{'} (x) = z J H (x) y (x)$ , $x \in (a, b)$ , whose Hamiltonian $H$ is non-negative and locally integrable, and where Weyl's li…

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…