Schedule for the Dynamical Systems and Differential Equations Seminar
University of Hamburg
Summer 2019

Friday 26. April 2019, 10:15, Geomatikum room 415. [Note: Different weekday, time and room than usual]
Speaker: Eddie Nijholt (University of Illinois, UrbanaChampaign)
Title: Simple expressions for the eigenvalues of linear network maps
Abstract: Network dynamical systems display many unusual properties that are unheard of for general ODEs.
Examples include complicated bifurcation scenarios, invariant subspaces and highly degenerate spectra.
I will focus on another peculiarity though, namely the observation that for many linear network maps the eigenvalues are given by simple, linear expressions of the coefficients.
My goal is to define and generalise such expressions (called network multipliers) and to show that they may be used to describe the spectrum of many network maps simultaneously.
Moreover, it will turn out that network multipliers are linearly independent, multiplicative,
and that they describe the spectrum of a network map for all choices of single node phase space at once.

Monday 6. May 2019, 14:15, Geomatikum room 415.
Speaker: Anton Jabs (Universität Hamburg)
Title: Stabilität und Bifurkationen in einem Verkehrsmodell mittels retardierter Differentialgleichungen
Abstract:

Friday 10. May 2019, 10:15, Geomatikum room 415.
Speaker: Jonathan Fenske (Universität Hamburg)
Title: Chaotische Dynamik in eindimensionalen dynamischen Systemen
Abstract:

Wednesday 15. Maj 2019, 10:15, Geomatikum room 241.
Speaker: Florian Noethen (Universität Hamburg)
Title: Wellseparated common complements of a sequence of subspaces of the same codimension in a Hilbert space
Abstract: Let V be a closed subspace of finite codimension and let C be a complementary subspace. The degree of transversality between
V and C can be quantified as the minimum distance a unit vector of C has to V. Denote this quantity by Psi(V,C). Then, Psi(V,C) ranges from 0
(not transversal) to 1 (orthogonal). Given closed subspaces (V_j)_j of the same codimension, we desire to find a common complement C with Psi(V_j,C)
as high as possible. For countably many subspaces, a common lower bound on Psi(V_j,C) cannot be expected. Instead we are looking for C s.t. Psi(V_j,C)
decays at most polynomially with j. Such a complement is called wellseparated. During the talk I will prove existence of wellseparated common
complements and argue why they are generic.

Montag 27. May 2019, 10:15, Geomatikum room 1438.
Speaker: Gordon Lisch (Universität Hamburg)
Title: Der Satz von PoincaréBendixson und Anwendungen in LotkaVolterra Systemen
Abstract:

Wednesday 29. Maj 2019, 10:15, Geomatikum room 241.
Speaker: TBA
Title: TBA
Abstract: TBA

Wednesday 19. Juni 2019, 10:15, Geomatikum room 241.
Speaker: Maximilian Voit (Jacobs University Bremen)
Title: Hierarchical heteroclinic cycles and separation of scales
Abstract: TBA

Wednesday 3. Juli 2019, 10:15, Geomatikum room 241.
Speaker: TBA
Title: TBA
Abstract: TBA