28 citations · 29 across the 7 of their papers we have counts for
8 papers
Fundamental group of compact decent spacetimes with lightlike hypersurface curvature
Raymond Hounnonkpe, Siba Kalivogui
In this paper, we study the fundamental group of compact de cent 4-dimensional spacetimes with lightlike hypersurface curvature. Such manifolds are foliated by totally geodesic nul…
Killing Vectors and Bochner-Type Theorems in Pseudo-Riemannian Hom-Lie Algebras
Raymond Hounnonkpe, Ibrahima Bakayoko, Emmanuel Gnandi +1
In this paper, we study pseudo-Riemannian Hom-Lie algebras. We establish Hom-versions of the classical Bochner theorem in both the Riemannian and Lorentzian settings. Finally, we p…
On the parity of the Betti numbers of 3-manifolds with a parallel vector field
Emmanuel Gnandi, Raymond A. Hounnonkpe
The question of whether a closed, orientable manifold can admit a nontrivial vector field that is parallel with respect to some Riemannian metric is a classical problem in Differen…
Compact Cauchy horizons admit constant surface gravity
Raymond A. Hounnonkpe, Ettore Minguzzi
We prove that in any spacetime dimension and under the null energy condition, every totally geodesic connected smooth compact null hypersurface (hence every compact Cauchy horizon)…
Riemannian flow techniques on totally geodesic null hypersurfaces
Manuel Gutiérrez, Raymond A. Hounnonkpe
We study the influence of the existence of totally geodesic null hypersurface on the properties of a Lorentzian manifold. By coupling the rigging technique with the existence of a…
Horizon classification via Riemannian flows
R. A. Hounnonkpe, E. Minguzzi
We point out that the geometry of connected totally geodesic compact null hypersurfaces in Lorentzian manifolds is only slightly more specialized than that of Riemannian flows over…
Regularity and temperature of stationary black hole event horizons
R. A. Hounnonkpe, E. Minguzzi
Available proofs of the regularity of stationary black hole event horizons rely on certain assumptions on the existence of sections that imply a differentiability assumption.…
Globally hyperbolic spacetimes can be defined without the 'causal' condition
R. A. Hounnonkpe, E. Minguzzi
Reasonable spacetimes are non-compact and of dimension larger than two. We show that these spacetimes are globally hyperbolic if and only if the causal diamonds are compact. That i…