Felix Klein was born on April 25, 1849 in Düsseldorf. On the occasion of his 170th birthday, the Felix Klein Colloquium will take place at the HHU. Thus, an old tradition of the Faculty of Mathematics at the HHU by Felix Klein Colloquia revives.

Date	Time	Speaker	Title
Thursday, May 9 at HHU Lecture hall 5F	15:00-16:00 16:00-16:30 Coffee break in Room 25.22.00.72 16:30-17:30	Michel Brion (Université Grenoble Alpes) Clara Löh (Universität Regensburg)	Automorphism groups of projective algebraic varieties The spectrum of simplicial volume: from groups to manifolds

Here are the abstracts of the talks:

Automorphism groups of projective algebraic varieties
Abstract: The talk will present classical and recent results on the structure of the automorphism group of a projective algebraic variety. This group is known to be an extension of a discrete group by a connected algebraic group; also, every connected algebraic group can be obtained in this way. The discrete part (the group of components) is much more mysterious: Lesieutre, Dinh and Oguiso have recently shown that this group is not necessarily finitely generated. On the other hand, the group of components turns out to be finitely presented for some interesting classes of varieties.

The spectrum of simplicial volume: from groups to manifolds
Abstract: Simplicial volume is a homotopy invariant of closed manifolds, defined as the minimal weighted number of singular simplices needed to represent the real fundamental class. Simplicial volume is related to rigidity phenomena in geometry and group theory in various ways. In this talk, I will give an introduction into the classical theory; moreover, I will outline the recent solution of the gap problem for simplicial volume, using group theory (joint work with Nicolaus Heuer).

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