Special Connections on Almost-Multifoliate Riemannian Manifolds.
Characteristic classes of subfoliations
This paper is devoted to define a characteristic homomorphism for a subfoliation and to study its relation with the usual characteristic homomorphism for each foliation (as defined by Bott). Moreover, two applications are given: 1) the Yamato’s 2-codimensional foliation is shown to be no homotopic to in a (1,2)-codimensional subfoliation; 2) an obstruction to the existence of everywhere independent and transverse infinitesimal transformations of a foliation is obtained, when and these...
Exotic characteristic classes and subfoliations
A topological obstruction for a foliation be a sub-foliation of another is given by comparing the images of the associated characteristic homomorphisms (in the sense of Lehmann).
Errata : Exotic characteristic classes and subfoliations
Examples of sectional curvature with prescribed symmetry on -manifolds
Nilpotent complex structures.
Este artículo presenta un panorama de algunos resultados recientes sobre estructuras complejas nilpotentes J definidas sobre nilvariedades compactas. Tratamos el problema de clasificación de nilvariedades compactas que admiten una tal J, el estudio de un modelo minimal de Dolbeault y su formalidad, y la construcción de estructuras complejas nilpotentes para las cuales la sucesión espectral de Frölicher no colapsa en el segundo término.
Compact symplectic four solvmanifolds without polarizations
Abelian complex structures on 6-dimensional compact nilmanifolds
We classify the -dimensional compact nilmanifolds that admit abelian complex structures, and for any such complex structure we describe the space of symplectic forms which are compatible with .
Existence of -almost tangent structures
Lie groups with no left invariant complex structures
Examples of compact complex manifolds with no Kahler structure
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