Connections on central bimodules

We define and study the theory of derivation-based connections on a recently introduced class of bimodules over an algebra which reduces to the category of modules whenever the algebra is commutative. This theory contains, in particular, a noncommutative generalization of linear connections. We also discuss the different noncommutative versions of differential forms based on derivations. Then we investigate reality conditions and a noncommutative generalization of pseudo-riemannian structures.Comment: 27 pages, AMS-LaTe

Higgs Mass and Noncommutative Geometry

We show that the description of the electroweak interactions based on noncommutative geometry of a continuous and a discrete space gives no special relations between the Higgs mass and other parameters of the model. We prove that there exists a gauge invariant term, linear in the curvature, which is trivial in the standard differential geometry but nontrivial in the case of the discrete geometry. The relations could appear only if one neglects this term, otherwise one gets the Lagrangian of the Standard model with the exact number of free parameters.Comment: 23 pages LaTeX, TPJU 4/93, (minor text misprints corrected

A bigraded version of the Weil algebra and of the Weil homomorphism for Donaldson invariants

We describe a bigraded generalization of the Weil algebra, of its basis and of the characteristic homomorphism which besides ordinary characteristic classes also maps on Donaldson invariants.Comment: 19 page

Rereading Frye: the published and unpublished works

Review of "Rereading Frye: The published and unpublished works" edited by David Boyd and Imre Salusinszk

Exeter College, Oxford lecture

Exeter College, Oxford lectur

Letters to the Editor

Dubois Patrick. KERGOMARD (Mme Pauline). In: , . Le dictionnaire de pédagogie et d'instruction primaire de Ferdinand Buisson : répertoire biographique des auteurs. Paris : Institut national de recherche pédagogique, 2002. pp. 90-91. (Bibliothèque de l'Histoire de l'Education, 17

GLAST Status and Application to Microquasars

The Gamma-ray Large Area Space Telescope (GLAST) is a next generation high energy gamma-ray observatory due for launch in Fall 2007. The primary instrument is the Large Area Telescope (LAT), which will measure gamma-ray flux and spectra from 20 MeV to > 300 GeV and is a successor to the highly successful EGRET experiment on CGRO. The LAT will have better angular resolution, greater effective area, wider field of view and broader energy coverage than any previous experiment in this energy range. An overview of the LAT instrument design and construction is presented which includes performance estimates with particular emphasis on how these apply to strudies of microquasars. The nature and quality of the data that will be provided by the LAT is described with results from recent detailed simulations that illustrate the potential of the LAT to observe gamma ray variability and spectra.Comment: 5 pages, 4 figures. Accepted for publication in the proceedings of VI Microquasar Workshop: Microquasars and Beyond, 18-22 September 2006, Como (Italy), ed: T. Belloni (2006