3 citations · 14 across the 22 of their papers we have counts for
37 papers
A solution to Crouzeix's conjecture
Emiel Lorist, Felix Schwenninger
We provide a proof of Crouzeix's conjecture, which combines the tools developed previously for weaker estimates with a simple perturbation lemma for -dilations. Applying the lem…
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…
BIBO stability of 1-D hyperbolic boundary control systems
Felix L. Schwenninger, Alexander A. Wierzba
We study the question of bounded-input bounded-output (BIBO) stability of a class of 1-D hyperbolic boundary control systems, which, in particular, contains distributed port-Hamilt…
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…
A universal example for quantitative semi-uniform stability
Sahiba Arora, Felix Schwenninger, Ingrid Vukusic +1
We characterise quantitative semi-uniform stability for -semigroups arising from port-Hamiltonian systems, complementing recent works on exponential and strong stability. With…
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…