Let $H_n$ be the Heisenberg group of dimension $2n+1$. Let ${\mathcal{L}}_1,\mathrm{\dots },{\mathcal{L}}_n$ be the partial sub-Laplacians on $H_n$ and $T$ the central element of the Lie algebra of $H_n$. We prove that the kernel of the operator $m\left({\mathcal{L}}_1,\mathrm{\dots },{\mathcal{L}}_n,-iT\right)$ is in the Schwartz space $S\left(H_n\right)$ if $m\in S\left({\mathbb{R}}^{n+1}\right)$. We prove also that the kernel of the operator $h\left({\mathcal{L}}_1,\mathrm{\dots },{\mathcal{L}}_n\right)$ is in $S\left(H_n\right)$ if $h\in S\left({\mathbb{R}}^n\right)$ and that the kernel of the operator $g\left(\mathcal{L},-iT\right)$ is in $S\left(H_n\right)$ if $g\in S\left({\mathbb{R}}^2\right)$. Here $\mathcal{L}={\mathcal{L}}_1+\mathrm{\dots }+{\mathcal{L}}_n$ is the Kohn-Laplacian on $H_n$.

Dans la première partie on caractérise les opérateurs différentiels invariants sur un groupe de Lie compact qui possèdent diverses propriétés de résolubilité analytiques : pour cela on développe en séries de Fourier les fonctions analytiques et les hyperfonctions sur le groupe.La deuxième partie est l’étude de la résolubilité des opérateurs invariants sur un groupe complexe réductif dans l’espace des fonctions holomorphes ; on développe celles-ci en série de “Laurent” suivant un sous-groupe compact...

Let $H_n$ be the (2n+1)-dimensional Heisenberg group, let p,q be two non-negative integers satisfying p+q=n and let G be the semidirect product of U(p,q) and $H_n$. So $L^2\left(H_n\right)$ has a natural structure of G-module. We obtain a decomposition of $L^2\left(H_n\right)$ as a direct integral of irreducible representations of G. On the other hand, we give an explicit description of the joint spectrum σ(L,iT) in $L^2\left(H_n\right)$ where $L={\sum }_{j=1}^p(X_j^2+Y_j^2)-{\sum }_{j=p+1}^n(X_j^2+Y_j^2)$, and where $X_1,Y_1,...,X_n,Y_n,T$ denotes the standard basis of the Lie algebra of $H_n$. Finally, we obtain a spectral characterization of the...

Let G be a Lie group, Xj right invariant vector fields on G, which generate (as a Lie algebra) the Lie algebra of G,L = -Σ Xj2.(...) In this paper we consider L1(G) boundedness of F(L) for (some) metabelian G and a distinguished L on G. Of the main interest is that the group is of exponential growth, and possibly higher rank. Previously positive results about higher rank groups were only about Iwasawa type groups. Also, our groups may be unimodular, so it is the second positive result (after [13])...