Cellular Actions and Groups of Finite Quasi-Projective Dimension.
A finite group G is called a gap group if there exists an ℝG-module which has no large isotropy groups except at zero and satisfies the gap condition. The gap condition facilitates the process of equivariant surgery. Many groups are gap groups and also many groups are not. In this paper, we clarify the relation between a gap group and the structures of its centralizers. We show that a nonsolvable group which has a normal, odd prime power index proper subgroup is a gap group.
Dans la première partie de ce travail, on prouve l’existence de champs stratifiés dits totalement radiaux sur un ensemble stratifié abstrait (e.s.a.). Ces champs sont stables et peuvent être choisis continus sur les espaces stratifiés plongés qui sont -réguliers au sens de K. Bekka. Dans la seconde partie, on établit pour ces espaces un théorème de Poincaré-Hopf pour les champs totalement radiaux continus. On en déduit un résultat similaire pour les e.s.a.
The authors generalize a construction of Connes by defining for an -bundle over smooth manifold and a reduced cyclic cohomology class a sequence of de Rham cohomology classes . Here is a convenient algebra, defined by the authors, and is a locally trivial bundle with standard fibre a right finitely generated projective -module and bounded -modules homomorphisms as transition functions.
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...
In this paper a construction of characteristic classes for a subfoliation is given by using Kamber-Tondeur’s techniques. For this purpose, the notion of -foliated principal bundle, and the definition of its associated characteristic homomorphism, are introduced. The relation with the characteristic homomorphism of -foliated bundles, , the results of Kamber-Tondeur on the cohomology of --algebras. Finally, Goldman’s results on the restriction of foliated bundles to the leaves of a foliation...