5 papers
Pseudo-Conformal actions of semisimple Lie groups
Mehdi Belraouti, Mohamed Deffaf, Abdelghani Zeghib
We consider the pseudo-Riemannian Lichnerowicz conjecture in the homogeneous setting. In particular, we show that any compact connected pseudo-Riemannian manifold on which a se…
On homogeneous holomorphic conformal structures
Mehdi Belraouti, Mohamed Deffaf, Yazid Raffed +1
We study compact complex manifolds admitting a conformal holomorphic Riemannian structure invariant under the action of a complex semi-simple Lie group . We prove that if th…
Pseudo-Conformal Actions of the M{ö}bius Group
Mehdi Belraouti, Mohamed Deffaf, Yazid Raffed +1
We study compact connected pseudo-Riemannian manifolds on which the conformal group acts essentially and transitively. We prove, in particular, t…
Actions of noncompact semisimple groups on Lorentz manifolds
Mohamed Deffaf, Karin Melnick, Abdelghani Zeghib
The above title is the same, but with "semisimple" instead of "simple," as that of a notice by N. Kowalsky. There, she announced many theorems on the subject of actions of simple L…
On Lorentz dynamics : From group actions to warped products via homogeneous spaces
Abdelouahab Arouche, Mohamed Deffaf, Abdelghani Zeghib
We show a geometric rigidity of isometric actions of non compact (semisimple) Lie groups on Lorentz manifolds. Namely, we show that the manifold has a warped product structure of a…