Résumé : A subgroup of a group is confined if the closure of its conjugacy class in the Chabauty space does not contain the trivial subgroup. Such subgroups arise naturally as stabilisers for non-free actions on compact spaces. I will explain a result establishing a relation between the confined subgroup of a group with its highly transitive actions. We will see how this result allows to understand the highly transitive actions of a class of groups of dynamical origin. This is joint work with Adrien Le Boudec.

Keywords : confined subgroups; highly transitive action; groups of PL homeomorphisms