The research seminars Analysis & Geometry (A&G)  and Dynamical Systems & Mathematical Physics (DS&MP) are organised by the research groups of Prof. David Hasler, Prof. Daniel Lenz, Prof. Vladimir Matveev, Prof. Tobias Jäger and Prof. Thomas Wannerer.

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When: Thursdays @ 14:30-16:00 (A&G) and 16:00-17:30 (DS&MP)

Where: The event takes place online via Zoom.
Everyone who wants to participate and does not have a password yet, please contact Markus Dafinger by e-mail.

Winter term 2020/21

26. November 2020

14:30-16:00 (A&G)

Prof. Karin Hanley Melnick (University of Maryland)

A D'Ambra Theorem in conformal Lorentzian geometry

Abstract: D'Ambra proved in 1988 that the isometry group of a compact, simply connected, real-analytic Lorentzian manifold must be compact. I will discuss my recent theorem that the conformal group of such a manifold must also be compact, and how it relates to the Lorentzian Lichnerowicz Conjecture.

(Contact: V. Matveev / M. Dafinger)
Everyone who wants to participate and does not have a password yet, please contact Markus Dafinger by e-mail.

19. November 2020

14:30-16:00 (A&G)

Dr. Shaosai Huang (University of Wisconsin)

Topological rigidity of the first Betti number and Ricci flow smoothing

Abstract: The infranil fiber bundle is a typical structure appeared in the collapsing geometry with bounded sectional curvature. In this talk, I will discuss a topological condition on the first Betti numbers that guarantees a torus fiber bundle structure (a special type of infranil fiber bundle) for collapsing manifolds with only Ricci curvature bounded below. The main technique applied here is smoothing by Ricci flows. This covers my joint with Bing Wang.

(Contact: V. Matveev / M. Dafinger)
Everyone who wants to participate and does not have a password yet, please contact Markus Dafinger by e-mail.

12. November 2020

14:30-16:00 (A&G)

Silvan Bernklau (Universität Jena)

The spectral mapping theorem for C₀-semigroups

Abstract: Two known proofs of the spectral mapping theorem for eventually norm continuous semigroups are presented, one exploiting individual properties of subcomponents of the spectrum and one relying on a representation of the spectrum in abelian Banach algebras.

(Contact: V. Matveev)