Orateur: Dominik Francoeur
Titre: From Free groups to Outer Space.
Résumé: In order to better understand a group, it is often fruitful to look at spaces on which this group acts in a nice way. Guided by this general principle, Marc Culler and Karen Vogtmann introduced in 1986 a space called Outer Space in order to better understand the outer automorphisms of free groups, which, despite being studied for many decades, were still very mysterious. In this talk, we will discuss the creation of Outer Space and the motivation behind it.

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