Universität Augsburg
Institut für Mathematik

Siegel der Universität Augsburg


Oberseminar Differentialgeometrie


Professor Sobhan Seyfaddini
Sorbonne Université, Paris

spricht am
Montag, 8. November 2021
16:15 Uhr
1009/L und Zoom (hybride Veranstaltung)
über das Thema:

»The algebraic structure of groups of area-preserving homeomorphisms«

I will review recent joint work with Dan Cristofaro-Gardiner, Vincent Humilière, Cheuk Yu Mak and Ivan Smith proving the following results : 1. In the 1970s, Fathi asked whether the group of Hamiltonian homeomorphisms of a compact surface is simple or not; we prove that the answer is no. The same question, for volume preserving homeomorphisms, was settled by Fathi in the 70. 2. In the mid 2000s, Fathi conjectured that the Calabi homomorphism admits an extension to a certain subgroup of Hamiltonian homeomorphisms, called Hameomorphisms, which was constructed by Oh-Muller. We present a proof of this conjecture.

Our main tool is a family of quantitative invariants, of Hamiltonian diffeomorphisms, arising from Lagrangian Floer homology.

If you want to take part via Zoom please ask Prof. Urs Frauenfelder for­ login details.


Hierzu ergeht herzliche Einladung.
Prof. Dr. Urs Frauenfelder

Kaffee, Tee und Gebäck eine halbe Stunde vor Vortragsbeginn im Raum 2006 (L1).

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