104 citations · 288 across the 40 of their papers we have counts for
7 papers · 2 filters
A sharp bound for the functional calculus of -contractions
Felix L. Schwenninger, Jens de Vries
Let be a -contraction and a rational function mapping the closed unit disk into itself. With a new characterization of -contractions we prove that \begin{align*} \big…
The algebraic numerical range as a spectral set in Banach algebras
Hanna Blazhko, Daniil Homza, Felix L. Schwenninger +2
We investigate when the algebraic numerical range is a -spectral set in a Banach algebra. While providing several counterexamples based on classical ideas as well as combinatori…
The double-layer potential for spectral constants revisited
F. L. Schwenninger, J. de Vries
We thoroughly analyse the double-layer potential's role in approaches to spectral sets in the spirit of Delyon--Delyon, Crouzeix and Crouzeix--Palencia. While the potential is well…
Continuous maximal regularity in locally convex spaces
Karsten Kruse, Felix L. Schwenninger
We study maximal regularity with respect to continuous functions for strongly continuous semigroups on locally convex spaces as well as its relation to the notion of admissible ope…
Admissible operators for sun-dual semigroups
Sahiba Arora, Felix L. Schwenninger
We extend classical duality results by Weiss on admissible operators to settings where the dual semigroup lacks strong continuity. This is possible using the sun-dual framework, wh…
The lattice structure of negative Sobolev and extrapolation spaces
Sahiba Arora, Jochen Glück, Felix L. Schwenninger
It is well-known that the Sobolev spaces are vector lattices with respect to the pointwise almost everywhere order if , but not if .…
Limit-case admissibility for positive infinite-dimensional systems
Sahiba Arora, Jochen Glück, Lassi Paunonen +1
In the context of positive infinite-dimensional linear systems, we systematically study -admissible control and observation operators with respect to the limit-cases $p=\infty…