Foreword
In this note, we study formal deformations of derived representations of the principal series representations of . In particular, we recover all the representations of the derived principal series by deforming one of them. Similar results are also obtained for .
Let be a compact Lie group acting in a Hamiltonian way on a symplectic manifold which is pre-quantized by a Kostant-Souriau line bundle. We suppose here that the moment map is proper so that the reduced space is compact for all . Then, we can define the “formal geometric quantization” of asThe aim of this article is to study the functorial properties of the assignment .
We review topological properties of Kähler and symplectic manifolds, and of their odd-dimensional counterparts, coKähler and cosymplectic manifolds. We focus on formality, Lefschetz property and parity of Betti numbers, also distinguishing the simply-connected case (in the Kähler/symplectic situation) and the b1 = 1 case (in the coKähler/cosymplectic situation).
Let be a differential manifold. Let be a Drinfeld associator. In this paper we explain how to construct a global formality morphism starting from . More precisely, following Tamarkin’s proof, we construct a Lie homomorphism “up to homotopy" between the Lie algebra of Hochschild cochains on and its cohomology ). This paper is an extended version of a course given 8 - 12 March 2004 on Tamarkin’s works. The reader will find explicit examples, recollections on -structures, explanation of the...
We study the formation of singularities for hypersurfaces evolving by mean curvature. After recalling the basic properties of the flow and the classical results about curves and convex surfaces, we give account of some recent developments of the theory for the case of surfaces with positive mean curvature. We show that for such surfaces we can obtain a–priori estimates on the principal curvatures which enable us to classify the singular profiles by the use of rescaling techniques.
On donne une construction de formes de contact sur toute variété décomposable en somme connexe de variétés de contact en toute dimension.