This book presents the foundations of the theory of groups and semigroups acting
isometrically on Gromov hyperbolic metric spaces. Particular emphasis is paid to the …

We study actions of higher rank lattices $\Gamma< G $ on hyperbolic spaces, and we show
that all such actions satisfying mild properties come from the rank-one factors of $ G $. In …

In this survey article, we present some panorama of groups acting on metric spaces of non-
positive curvature. We introduce the main examples and their rigidity properties, we show …

We define a Toledo number for actions of surface groups and complex hyperbolic lattices on
infinite-dimensional Hermitian symmetric spaces, which allows us to define maximal …

On the one hand, we construct a continuous family of non-isometric proper ${\rm CAT}(-1) $
spaces on which the isometry group ${\rm Isom}({\bf H}^ n) $ of the real hyperbolic $ n …

A finitely presented group is called a Kähler group if it can be realized as the fundamental
group of a compact Kähler manifold. The study of Kähler groups consists in establishing …

We associate to any Riemannian symmetric space (of finite or infinite dimension) a L∗-
algebra, under the assumption that the curvature operator has a fixed sign. L∗-algebras are …

We prove that an IRS of a group with a geometrically dense action on a CAT (0) space also
acts geometrically densely; assuming the space is either of finite telescopic dimension or …

Dans cette thèse, on étudie des marches aléatoires induites par des actions de groupes
probabilisés sur des espaces de courbure négative ou nulle. On décrit en particulier le cas …

We consider actions of locally compact groups G on certain CAT (0) spaces X by isometries.
The CAT (0) spaces we consider have finite dimension at large scale. In case B is a G …