Group Actions and Curvature.
Group actions, gauge transformations, and the calculus of variations.
Group -algebras as compact quantum metric spaces.
Groupes automatiques et courbure négative (d'après D.B.A. Epstein)
Groupes conformes en relativité générale
Groupes de Ping-Pong et comptage
Dans cet article, nous étudions les propriétés asymptotiques d’une large classe de sous-groupe discrets du groupe linéaire réel : les groupes de Ping-Pong. Nous décrivons leur action sur l’espace projectif réel et le comportement à l’infini de leur fonction de comptage.
Groupes de Schottky et comptage
Soient un espace symétrique de type non compact et un groupe discret d’isométries de du type de Schottky. Dans cet article, nous donnons des équivalents des fonctions orbitales de comptage pour l’action de sur .
Groupes de spinorialité
Groupes du ping-pong et géodésiques fermées en courbure -1
Nous considérons une famille de groupes libres et discrets d’isométries orientées agissant sur la boule hyperbolique et contenant des transformations paraboliques; nous démontrons que le nombre de géodésiques fermées de de longueur au plus est équivalent à , où désigne l’exposant critique de la série de Poincaré.
Groupoïdes riemanniens.
We propose a definition of a Riemannian groupoid, and we show that the Stefan foliation that it induces is a Riemannian (singular) foliation. We also prove that the homotopy groupoid of a Riemannian (regular) foliation is a Riemannian groupoid.
Groups in the category of f-manifolds
Groups of Isometric Transformations, Basic Connections and Splitting results on Riemannian Manifolds
Groups of transformations of a G-structure whic H leave invariant a substructure.
Growth of a primitive of a differential form
For an exact differential form on a Riemannian manifold to have a primitive bounded by a given function , by Stokes it has to satisfy some weighted isoperimetric inequality. We show the converse up to some constants if has bounded geometry. For a volume form, it suffices to have the inequality ( for every compact domain ). This implies in particular the “well-known” result that if is the universal covering of a compact Riemannian manifold with non-amenable fundamental group, then the volume...
Growth of homogeneous spaces, density of discrete subgroups and Kazhdan's property (T).
Growth of Jacobi Fields and Divergence of Geodesics.
Growth of weighted volume and some applications
We define cut-off functions in order to allow higher growth for Dirichlet energy. Our results are generalizations of the classical Cheng-Yau’s growth conditions of parabolicity. Finally we give some applications to the function theory of Kähler and quaternionic-Kähler manifolds.
Grundgleichungen der Stereologie II.
G-Spaces, the Asymptotic Splitting of L2(M) into Irreducibles.
G-structures of second order defined by linear operators satisfying algebraic relations.
The present work is based on a type of structures on a differential manifold V, called G-structures of the second kind, defined by endomorphism J on the second order tangent bundle T2(V ). Our objective is to give conditions for a differential manifold to admit a real almost product and a generalised almost tangent structure of second order. The concepts of the second order frame bundle H2(V ), its structural group L2 and its associated tangent bundle of second order T2(V ) of a differentiable manifold...