91 citations · 244 across the 32 of their papers we have counts for
17 papers · 1 filter
A Lumer-Phillips type generation theorem for bi-continuous semigroups
Christian Budde, Sven-Ake Wegner
The famous 1960s Lumer-Phillips Theorem states that a closed and densely defined operator on a Banach space generates a strongly continuo…
Lecture notes on high-dimensional data
Sven-Ake Wegner
These are lecture notes based on the first part of a course on 'Mathematical Data Science', which I taught to final year BSc students in the UK in 2019-2020. Topics include: concen…
Dissipative extensions and port-Hamiltonian operators on networks
Marcus Waurick, Sven-Ake Wegner
In this article we study port-Hamiltonian partial differential equations on certain one-dimensional manifolds. We classify those boundary conditions that give rise to contraction s…
Well-posedness of a class of hyperbolic partial differential equations on the semi-axis
Birgit Jacob, Sven-Ake Wegner
In this article we study a class of hyperbolic partial differential equations of order one on the semi-axis. The so-called port-Hamiltonian systems cover for instance the wave equa…
Some remarks on the notions of boundary systems and boundary triple(t)s
Marcus Waurick, Sven-Ake Wegner
In this note we show that if a boundary system in the sense of (Schubert et al. 2015) gives rise to any skew-self-adjoint extension, then it induces a boundary triplet and the clas…
Boundary triplets for skew-symmetric operators and the generation of strongly continuous semigroups
Sven-Ake Wegner
We give a self-contained and streamlined exposition of a generation theorem for C0-semigroups based on the method of boundary triplets. We apply this theorem to port-Hamiltonian sy…
Pivot duality of universal interpolation and extrapolation spaces
Christian Bargetz, Sven-Ake Wegner
It is a widely used method, for instance in perturbation theory, to associate with a given C0-semigroup its so-called interpolation and extrapolation spaces. In the model case of t…
Non power bounded generators of strongly continuous semigroups
Anna Golińska, Sven-Ake Wegner
It is folklore that a power bounded operator on a sequentially complete locally convex space generates a uniformly continuous -semigroup which is given by the corresponding po…
Desch-Schappacher Perturbation of One-Parameter Semigroups on Locally Convex Spaces
Birgit Jacob, Sven-Ake Wegner, Jens Wintermayr
We prove a Desch-Schappacher type perturbation theorem for strongly continuous and locally equicontinuous one-parameter semigroups which are defined on a sequentially complete loca…
The growth bound for strongly continuous semigroups on Fréchet spaces
Sven-Ake Wegner
We introduce the concepts of growth and spectral bound for strongly continuous semigroups acting on Fréchet spaces and show that the Banach space inequality e…
Maximal exact structures on additive categories
Dennis Sieg, Sven-Ake Wegner
We show that every additive category with kernels and cokernels admits a maximal exact structure. Moreover, we discuss two examples of categories of the latter type arising from fu…
Bornological projective limits of inductive limits of normed spaces
José Bonet, Sven-Ake Wegner
We establish a criterion to decide when a countable projective limit of countable inductive limits of normed spaces is bornological. We compare the conditions occurring within our…
Universal extrapolation spaces for C-semigroups
Sven-Ake Wegner
The classical theory of Sobolev towers allows for the construction of an infinite ascending chain of extrapolation spaces and an infinite descending chain of interpolation spaces a…
Projective limits of weighted LB-spaces of holomorphic functions
Sven-Ake Wegner
Countable projective limits of countable inductive limits, called PLB-spaces, of weighted Banach spaces of continuous functions have recently been investigated by Agethen, Biersted…
PLB-spaces of holomorphic functions with logarithmic growth conditions
Sven-Ake Wegner
Countable projective limits of countable inductive limits, called PLB-spaces, of weighted Banach spaces of continuous functions have recently been investigated by Agethen, Biersted…
Weighted PLB-spaces of continuous functions arising as tensor products of a Fréchet and a DF-space
Sven-Ake Wegner
Countable projective limits of countable inductive limits, so-called PLB-spaces, of weighted Banach spaces of continuous functions have recently been investigated by Agethen, Biers…
Notes on a proof of Bonet, Engliš and Taskinen
Sven-Ake Wegner
We give a proof of a result of Bonet, Engliš and Taskinen filling in several details and correcting some flaws.