Characteristic classes of multifoliations
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...
Si fa vedere che alcune classi di Chern di fibrati vettoriali complessi possono essere costruite non solo partendo da connessioni ma, sotto certe condizioni, anche da connessioni lineari singolari. Nel caso particolare del fibrato tangente possono essere costruite anche a partire da metriche singolari. Viene fatto uso in modo essenziale della -coomologia di de Rham (introdotta da Cheeger e Teleman).