Geometry of biinvariant subsets of complex semisimple Lie groups
We show that infinitesimal automorphisms and infinitesimal deformations of parabolic geometries can be nicely described in terms of the twisted de Rham sequence associated to a certain linear connection on the adjoint tractor bundle. For regular normal geometries, this description can be related to the underlying geometric structure using the machinery of BGG sequences. In the locally flat case, this leads to a deformation complex, which generalizes the well known complex for locally conformally...
Let be a relatively closed subset of a Stein manifold. We prove that the -cohomology groups of Whitney forms on and of currents supported on are either zero or infinite dimensional. This yields obstructions of the existence of a generic embedding of a CR manifold into any open subset of any Stein manifold, namely by the nonvanishing but finite dimensionality of some intermediate -cohomology groups.
Convergence of special Green integrals for matrix factorization of the Laplace operator in is proved. Explicit formulae for solutions of -equation in strictly pseudo-convex domains in are obtained.
There is a well known one–parameter family of left invariant CR structures on . We show how purely algebraic methods can be used to explicitly compute the canonical Cartan connections associated to these structures and their curvatures. We also obtain explicit descriptions of tractor bundles and tractor connections.
In this paper we develop a method to compute the Burns-Epstein invariant of a spherical CR homology sphere, up to an integer, from its holonomy representation. As an application, we give a formula for the Burns-Epstein invariant, modulo an integer, of a spherical CR structure on a Seifert fibered homology sphere in terms of its holonomy representation.
L’étude du « problème de Plateau complexe » (ou « problème du bord ») dans une variété complexe consiste à caractériser les sous-variétés réelles de qui sont le bord de sous-ensembles analytiques de . Notre principal résultat traite le cas où est une variété complexe connexe et est une variété kählérienne disque convexe. Comme conséquence, nous obtenons des résultats de Harvey-Lawson [19], Dolbeault-Henkin [12] et Dinh [10]. Nous obtenons aussi une généralisation des théorèmes de Hartogs-Levi...