Product preserving bundles on foliated manifolds
We present a complete description of all product preserving bundle functors on the category ℱol of all foliated manifolds and their leaf respecting maps in terms of homomorphisms of Weil algebras.
We present a complete description of all product preserving bundle functors on the category ℱol of all foliated manifolds and their leaf respecting maps in terms of homomorphisms of Weil algebras.
We consider projectively Anosov flows with differentiable stable and unstable foliations. We characterize the flows on which can be extended on a neighbourhood of into a projectively Anosov flow so that is a compact leaf of the stable foliation. Furthermore, to realize this extension on an arbitrary closed 3-manifold, the topology of this manifold plays an essential role. Thus, we give the classification of projectively Anosov flows on . In this case, the only flows on which extend to ...
Nous montrons que le prolongement des homotopies, propriété de certains feuilletages étudiée par Godbillon, équivaut à la réunion de trois conditions indépendantes : la condition de Barre, qui est transverse ; la trivialité des cycles évanouissants de toutes dimensions, et la trivialité des cycles apparents de toutes dimensions. On établit que pour les feuilletages riemanniens et pour les feuilletages géodésibles, la propriété équivaut à l’absence d’holonomie. Ces résultats sont ensuite appliqués...
This paper is a continuation of Part I of the same title which has appeared at the last issue of this journal.
C’est un article sur les publications mathématiques pendant l’Occupation (1940–44). À travers les cas de quatre mathématiciens, et surtout de celui de Jacques Feldbau (un des fondateurs de la théorie des fibrés, mort en déportation), nous étudions la façon dont la censure a frappé les mathématiciens français définis comme juifs par le « Statut des juifs » d’octobre 1940 et les stratégies de publication que ceux-ci ont alors utilisées (pseudonymes, plis cachetés, journaux provinciaux...) La manière...
A construction of the noncommutative-geometric counterparts of classical classifying spaces is presented, for general compact matrix quantum structure groups. A quantum analogue of the classical concept of the classifying map is introduced and analyzed. Interrelations with the abstract algebraic theory of quantum characteristic classes are discussed. Various non-equivalent approaches to defining universal characteristic classes are outlined.
We give criteria for framed links and 3-manifolds to be periodic of prime order. As applications we show that the Poincaré sphere is of periodicity 2, 3, 5 only and the Brieskorn sphere Σ(2,3,7) is of periodicity 2, 3, 7 only.
We propose a direction of study of nonabelian theta functions by establishing an analogy between the Weyl quantization of a one-dimensional particle and the metaplectic representation on the one hand, and the quantization of the moduli space of flat connections on a surface and the representation of the mapping class group on the space of nonabelian theta functions on the other. We exemplify this with the cases of classical theta functions and of the nonabelian theta functions for the gauge group...
A general theory of characteristic classes of quantum principal bundles is presented, incorporating basic ideas of classical Weil theory into the conceptual framework of noncommutative differential geometry. A purely cohomological interpretation of the Weil homomorphism is given, together with a geometrical interpretation via quantum invariant polynomials. A natural spectral sequence is described. Some interesting quantum phenomena appearing in the formalism are discussed.