Berezin-Toeplitz quantization for compact Kaehler manifolds. A Review of Results

This article is a review on Berezin-Toeplitz operator and Berezin-Toeplitz deformation quantization for compact quantizable Kaehler manifolds. The basic objects, concepts, and results are given. This concerns the correct semi-classical limit behaviour of the operator quantization, the unique Berezin-Toeplitz deformation quantization (star product), covariant and contravariant Berezin symbols, and Berezin transform. Other related objects and constructions are also discussed.Comment: 32 page

Foliation groupoids and their cyclic homology

In this paper we study the Lie groupoids which appear in foliation theory. A foliation groupoid is a Lie groupoid which integrates a foliation, or, equivalently, whose anchor map is injective. The first theorem shows that, for a Lie groupoid G, the following are equivalent: - G is a foliation groupoid, - G has discrete isotropy groups, - G is Morita equivalent to an etale groupoid. Moreover, we show that among the Lie groupoids integrating a given foliation, the holonomy and the monodromy groupoids are extreme examples. The second theorem shows that the cyclic homology of convolution algebras of foliation groupoids is invariant under Morita equivalence of groupoids, and we give explicit formulas. Combined with the previous results of Brylinski, Nistor and the authors, this theorem completes the computation of cyclic homology for various foliation groupoids, like the (full) holonomy/monodromy groupoid, Lie groupoids modeling orbifolds, and crossed products by actions of Lie groups with finite stabilizers. Some parts of the proof, such as the H-unitality of convolution algebras, apply to general Lie groupoids. Since one of our motivation is a better understanding of various approaches to longitudinal index theorems for foliations, we have added a few brief comments at the end of the second section.Comment: 18 page

Discrete compactness for the hp version of rectangular edge finite elements

International audienceDiscretization of Maxwell eigenvalue problems with edge finite elements involves a simultaneous use of two discrete subspaces of H^1 and H(rot), reproducing the exact sequence condition. Kikuchi's Discrete Compactness Property, along with appropriate approximability conditions, implies the convergence of discrete eigenpairs to the exact ones. In this paper we prove the discrete compactness property for the edge element approximation of Maxwell's eigenpairs on general hp adaptive rectangular meshes. Hanging nodes, yielding 1-irregular meshes, are covered, and the order of the used elements can vary from one rectangle to another, thus allowing for a real hp adaptivity. As a particular case, our analysis covers the convergence result for the p-method

Anabelian geometry and descent obstructions on moduli spaces

We study the section conjecture of anabelian geometry and the sufficiency of the finite descent obstruction to the Hasse principle for the moduli spaces of principally polarized abelian varieties and of curves over number fields. For the former we show that the section conjecture fails and the finite descent obstruction holds for a general class of adelic points, assuming several well-known conjectures. This is done by relating the problem to a local-global principle for Galois representations. For the latter, we prove some partial results that indicate that the finite descent obstruction suffices. We also show how this sufficiency implies the same for all hyperbolic curves.Comment: exposition improve