We give a geometric derivation of Branson's Q-curvature in terms of the ambient metric
associated with conformal structures; it naturally follows from the ambient metric construction …

We describe an elementary algorithm for expressing, as explicit formulae in tractor calculus,
the conformally invariant GJMS operators due to CR Graham et alia. These differential …

We derive sharp Moser-Trudinger inequalities on the CR sphere. The first type is in the
Adams form, for powers of the sublaplacian and for general spectrally defined operators on …

We show that the conformally invariant fractional powers of the sub-Laplacian on the
Heisenberg group are given in terms of the scattering operator for an extension problem to …

This memoir deals with the hypoelliptic calculus on Heisenberg manifolds, including CR and
contact manifolds. In this context the main differential operators at stake include the …

We initiate a new study of differential operators with symmetries and combine this with the
study of branching laws for Verma modules of reductive Lie algebras. By the criterion for …

We introduce a fourth order CR invariant operator on pluriharmonic functions on a three-
dimensional CR manifold, generalizing to the abstract setting the operator discovered by …

We show that on conformal manifolds of even dimension $ n\geq 4$ there is no conformally
invariant natural differential operator between density bundles with leading part a power of …

Q-prime curvature, which was introduced by J. Case and P. Yang, is a local invariant of
pseudo-hermitian structure on CR manifolds that can be defined only when the Q-curvature …

The aim of this paper is to establish higher order Poincaré-Sobolev, Hardy-Sobolev-Maz'ya,
Adams and Hardy-Adams inequalities on Siegel domains and complex hyperbolic spaces …