Orbit method and character formulas for tempered representations of a nonconnected reductive real algebraic group. (Méthode des orbites et formules du caractère pour les représentations tempérées d'un groupe algébrique réel réductif non connexe.)
Let G be a compact Lie group. We present a criterion for the orbit spaces of two G-spaces to be homotopy equivalent and use it to obtain a quick proof of Webb’s conjecture for compact Lie groups. We establish two Minami type formulae which present the p-localised spectrum as an alternating sum of p-localised spectra for subgroups H of G. The subgroups H are calculated from the collections of the non-trivial elementary abelian p-subgroups of G and the non-trivial p-radical subgroups of G. We...
Let ℒ be the sublaplacian on the Heisenberg group Hⁿ. A recent result of Müller and Stein shows that the operator is bounded on for all p satisfying |1/p - 1/2| < 1/(2n). In this paper we show that the same operator is bounded on in the bigger range |1/p - 1/2| < 1/(2n-1) if we consider only functions which are band limited in the central variable.
Tout parallélisme absolu d’une variété lorentzienne complète et simplement connexe respecte une décomposition de de Rham ; dans le cas faiblement irréductible mais non irréductible, la variété est un groupe de Lie résoluble.