Fermion on curved spaces, symmetries, and quantum anomalies.
Let be M a smooth manifold, A a local algebra and a manifold of infinitely near points on M of kind A. We build the canonical foliation on and we show that the canonical foliation on the tangent bundle TM is the foliation defined by its canonical field.
Dans cet article nous montrons que tout feuilletage conforme, transversalement analytique, de codimension supérieure ou égale à trois sur une variété compacte connexe est transversalement Möbius ou riemannien. Ce théorème peut être vu comme une généralisation, transversalement à un feuilletage, du théorème Ferrand-Obata.
On étudie, sur les surfaces compactes orientables, les feuilletages orientables (i.e. pouvant être définis par un champ de vecteurs) dont les singularités sont des selles. Ces feuilletages sont considérés modulo isotopies et opérations de Whitehead préservant l’orientabilité du feuilletage. Dans le première partie on définit les “feuilletages connexes”, ceux pour lesquels par deux points quelconques passe une transversable fermée. De façon équivalente, le feuilletage est la suspension d’un échange...
We give a description of Kähler manifolds equipped with an integrable subbundle of of rank () under the assumption that the line bundle is numerically trivial. This is a sort of foliated version of Bogomolov’s theorem concerning Kähler manifolds with trivial canonical class.
We introduce the concept of modified vertical Weil functors on the category of fibred manifolds with -dimensional bases and their fibred maps with embeddings as base maps. Then we describe all fiber product preserving bundle functors on in terms of modified vertical Weil functors. The construction of modified vertical Weil functors is an (almost direct) generalization of the usual vertical Weil functor. Namely, in the construction of the usual vertical Weil functors, we replace the usual Weil...
We describe the fiber product preserving bundle functors on the category of all morphisms of fibered manifolds in terms of infinite sequences of Weil algebras and actions of the skeleton of the category of -jets by algebra homomorphisms. We deduce an explicit formula for the iteration of two such functors. We characterize the functors with values in vector bundles.
We prove fibration theorems on compact Kähler manifolds with conditions on first cohomology groups of fundamental groups with respect to unitary representations into Hilbert spaces. If the fundamental group T of compact Kähler manifold X violates Property (T) of Kazhdan’s, then for some unitary representation . By our earlier work there exists a -closed holomorphic 1-form with coefficients twisted by some unitary representation , possibly non-isomorphic to . Taking norms we obtains a positive...