01.04.2026 - 4 pm (CEST) - Michał Wojtylak (Jagiellonian U Krakow)

Title: 

Linear algebra of dissipative Hamiltonian systems

Abstract: 

We will begin with a review of the Kronecker of pencils appearing in the port Hamiltonian modelling.  Although the task  seems to be completed by  [1], and [2], the transfer function considerations in [3] put a different light on these results. In the second part of the talk we will concentrate on the eigenvalue infinity, and the size of the largest Kronecker block - the index. We will study the perturbation properties of the eigenvalue infinity, presenting non-asymptotic results based on the Bauer-Fike theorem, see [4]. Several numerical examples will be considered.

[1] C. Mehl, V. Mehrmann, and M. Wojtylak. Matrix pencils with coefficients that have positive
semidefinite Hermitian parts. SIMAX 2022. 

[2] N. Gillis, V. Mehrmann, and P. Sharma. Computing the nearest stable matrix pairs. NLAA, 2018.

[3] K. Cherifi, H. Gernandt, and D. Hinsen. The difference between port-Hamiltonian, passive and
positive real descriptor systems. MCSS,  2024.

[4] H. Blazhko, M. Wojtylak, Detection of the higher order Kronecker blocks by perturbation, 2026 , preprint.

06.05.2026 - 4 pm (CEST) - Carsten Hartmann (BTU Cottbus-Senftenberg)

03.06.2026 - 4 pm (CEST) - Anthony Hastir (U Namur)

01.07.2026 - 4 pm (CEST) - tbd

Summer Break

02.09.2026 - 4 pm (CEST) - tbd

07.10.2026 - 4 pm (CEST) - tbd

04.11.2026 - 4 pm (CEST) - tbd

02.12.2026 - 4 pm (CEST) - tbd