100, rue des maths 38610 Gières / GPS : 45.193055, 5.772076 / Directeur : Louis Funar

Nicolas Matte Bon

Locally moving groups acting on intervals
Thursday, 25 March, 2021 - 14:00
Résumé : 

Given a group, we are interested in understanding and classifying its  
actions on one-dimensional manifolds, that its representations into  
the groups of homeomorphisms or diffeomorphisms of an interval or the  
circle. In this talk we will address this problem for a class of  
groups arising via an action on intervals of a special type, called  
locally moving. A well studied example in this class is the Thompson  
group. We will see that if G is a locally moving group of  
homeomorphisms of a real interval, then every action of G on an  
interval by diffeomorphisms (of class C^1) is semiconjugate to the  
natural defining action of G. In contrast such a group can admit a  
much richer space of actions on intervals by homeomorphisms, and we  
will investigate the structure of such actions. This is joint work  
with Joaquín Brum, Cristóbal Rivas and Michele Triestino.

Institution de l'orateur : 
Institut Camille Jordan
Thème de recherche : 
Théorie spectrale et géométrie
Salle : 
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