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Chern classes of vector bundles with singular connections

Guiseppe De Cecco (1982)

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

Si fa vedere che alcune classi di Chern di fibrati vettoriali complessi possono essere costruite non solo partendo da connessioni C 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 L 2 -coomologia di de Rham (introdotta da Cheeger e Teleman).

Classes caractéristiques exotiques et -connexité des espaces de connexions

Daniel Lehmann (1974)

Annales de l'institut Fourier

Le but de ce travail est double : d’une part, généraliser la construction des classes exotiques pour l’appliquer à d’autres problèmes géométriques que ceux issus des Γ -structures ; d’autre part, préciser, grâce à la notion de J -connexité, remplaçant avantageusement les formules de dérivation utilisées précédemment, l’argument d’invariance homotopique permettant d’obtenir des théorèmes de rigidité, montrant simultanément pourquoi la seule connexité des ensembles de connexions considérés ne suffit...

Classes caractéristiques réelles de certains G-fibrés vectorials et résidus.

Abdelhak Abouqateb (1998)

Publicacions Matemàtiques

This work is a contribution to study residues of real characteristic classes of vector bundles on which act compact Lie groups. By using the Cech-De Rham complex, the realisation of the usual Thom isomorphism permites us to illustrate localisation techniques of some topological invariants.

Cohomology of B O ( n 1 ) × × B O ( n m ) with local integer coefficients

Richard Lastovecki (2005)

Commentationes Mathematicae Universitatis Carolinae

Let 𝒵 be a set of all possible nonequivalent systems of local integer coefficients over the classifying space B O ( n 1 ) × × B O ( n m ) . We introduce a cohomology ring 𝒢 𝒵 H * ( B O ( n 1 ) × × B O ( n m ) ; 𝒢 ) , which has a structure of a ( 2 ) m -graded ring, and describe it in terms of generators and relations. The cohomology ring with integer coefficients is contained as its subring. This result generalizes both the description of the cohomology with the nontrivial system of local integer coefficients of B O ( n ) in [Č] and the description of the cohomology with integer...

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