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Infinitesimal automorphisms and deformations of parabolic geometries

Andreas Čap (2008)

Journal of the European Mathematical Society

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...

Obstructions to generic embeddings

Judith Brinkschulte, C. Denson Hill, Mauro Nacinovich (2002)

Annales de l’institut Fourier

Let F be a relatively closed subset of a Stein manifold. We prove that the ¯ -cohomology groups of Whitney forms on F and of currents supported on F are either zero or infinite dimensional. This yields obstructions of the existence of a generic C R embedding of a CR manifold M into any open subset of any Stein manifold, namely by the nonvanishing but finite dimensionality of some intermediate ¯ M -cohomology groups.

On iterations of Green type integrals for matrix factorizations of the Laplace operator

Alexandre A. Shlapunov (1994)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti Lincei. Matematica e Applicazioni

Convergence of special Green integrals for matrix factorization of the Laplace operator in R n is proved. Explicit formulae for solutions of ¯ -equation in strictly pseudo-convex domains in C n are obtained.

On left invariant CR structures on SU ( 2 )

Andreas Čap (2006)

Archivum Mathematicum

There is a well known one–parameter family of left invariant CR structures on S U ( 2 ) S 3 . 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.

On the Burns-Epstein invariants of spherical CR 3-manifolds

Khoi The Vu (2011)

Annales de l’institut Fourier

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.

Problème de Plateau complexe dans les variétés kählériennes

Frédéric Sarkis (2002)

Bulletin de la Société Mathématique de France

L’étude du « problème de Plateau complexe » (ou « problème du bord ») dans une variété complexe X consiste à caractériser les sous-variétés réelles  Γ de X qui sont le bord de sous-ensembles analytiques de X Γ . Notre principal résultat traite le cas X = U × ω U est une variété complexe connexe et ω 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...

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