7 citations · 17 across the 19 of their papers we have counts for
22 papers
Homomorphisms and subalgebras of free convex semilattices
Harald Woracek
A convex semilattices is a convex algebra endowed with an additional semilattice operation that satisfies a distributive law. We investigate free convex semilattices by studying th…
Convex algebras on an interval with semicontinuous monotone operations
Ana Sokolova, Harald Woracek
In a recent work of Matteo Mio on compact quantitative equational theories (here compact means that all its consequences are derivable by means of finite proofs) convex algebras on…
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…
Homogeneous spaces of entire functions
Benjamin Eichinger, Harald Woracek
Homogeneous spaces are de Branges' Hilbert spaces of entire functions with the property that certain weighted rescaling transforms induce isometries of the space into itself. A cla…
An upper bound for the Nevanlinna matrix of an indeterminate moment sequence
Raphael Pruckner, Jakob Reiffenstein, Harald Woracek
The solutions of an indeterminate Hamburger moment problem can be parameterised using the Nevanlinna matrix of the problem. The entries of this matrix are entire functions of minim…
Karamata's theorem for regularised Cauchy transforms
Matthias Langer, Harald Woracek
We prove Abelian and Tauberian theorems for regularised Cauchy transforms of positive Borel measures on the real line whose distribution functions grow at most polynomially at infi…
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…
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…
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…
Canonical systems whose Weyl coefficients have dominating real part
Matthias Langer, Raphael Pruckner, Harald Woracek
For a two-dimensional canonical system on the half-line whose Hamiltonian is a.e. positive semi-definite, denote by its Weyl coefficient.…
Nawrotzki's Algorithm for the Countable Splitting Lemma, Constructively
Ana Sokolova, Harald Woracek
We reprove the countable splitting lemma by adapting Nawrotzki's algorithm which produces a sequence that converges to a solution. Our algorithm combines Nawrotzki's approach with…
Limit behaviour of Weyl coefficients
Raphael Pruckner, Harald Woracek
We study the sets of radial or nontangential limit points towards of a Nevanlinna function q. Given a nonempty, closed, and connected subset L of , we explicitly co…
Estimates for the Weyl coefficient of a two-dimensional canonical system
Matthias Langer, Raphael Pruckner, Harald Woracek
For a two-dimensional canonical system on some interval whose Hamiltonian is a.e. positive semi-definite and which is regular at and in the limit…
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…
Proper Semirings and Proper Convex Functors
Ana Sokolova, Harald Woracek
Esik and Maletti introduced the notion of a proper semiring and proved that some important (classes of) semirings -- Noetherian semirings, natural numbers -- are proper. Properness…
Termination in Convex Sets of Distributions
Ana Sokolova, Harald Woracek
Convex algebras, also called (semi)convex sets, are at the heart of modelling probabilistic systems including probabilistic automata. Abstractly, they are the Eilenberg-Moore algeb…
Bounds on order of indeterminate moment sequences
Raphael Pruckner, Roman Romanov, Harald Woracek
We investigate the order of the four entire functions in the Nevanlinna matrix of an indeterminate Hamburger moment sequence. We give an upper estimate for which is explici…
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 , , whose Hamiltonian is non-negative and locally integrable, and where Weyl's li…
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…
De Branges' theorem on approximation problems of Bernstein type
Anton Baranov, Harald Woracek
The Bernstein approximation problem is to determine whether or not the space of all polynomials is dense in a given weighted -space on the real line. A theorem of L. de Brange…
Majorization in de Branges spaces II. Banach spaces generated by majorants
Anton Baranov, Harald Woracek
This is the second part in a series dealing with subspaces of de Branges spaces of entire function generated by majorization on subsets of the closed upper half-plane. In this part…
Majorization in de Branges spaces I. Representability of subspaces
Anton Baranov, Harald Woracek
In this series of papers we study subspaces of de Branges spaces of entire functions which are generated by majorization on subsets of the closed upper half-plane. The present,…