Hyperbolicité du graphe des rayons et quasi-morphismes sur un gros groupe modulaire
Hyperbolicité du graphe des rayons et quasi-morphismes sur un gros groupe modulaire
The mapping class group $\Gamma$ of the complement of a Cantor set in the plane arises naturally in dynamics. We show that the ray graph, which is the analog of the complex of curves for this surface of infinite type, has infinite diameter and is hyperbolic. We use the action …