24 citations · 65 across the 7 of their papers we have counts for
7 papers
On Thurston's geometrical space form problem: on quasi space forms
Stefan Haesen, Miroslava Petrović-Torgašev, Leopold Verstraelen
A proposal is made for what may well be the most elementary Riemannian spaces which are homogeneous but not isotropic. In other words: a proposal is made for what may well be the n…
New Examples of Marginally Trapped Surfaces and Tubes in Warped Spacetimes
J. L. Flores, S. Haesen, M. Ortega
In the present paper we provide new examples of marginally trapped surfaces and tubes in FLRW spacetimes by using a basic relation between these objects and CMC surfaces in 3-manif…
Marginally trapped surfaces in Minkowski 4-space invariant under a rotation subgroup of the Lorentz group
Stefan Haesen, Miguel Ortega
A local classification of spacelike surfaces in Minkowski 4-space, which are invariant under spacelike rotations, and with mean curvature vector either vanishing or lightlike, is o…
The Mean Curvature of the Second Fundamental Form of a hypersurface
Stefan Haesen, Steven Verpoort
An expression for the first variation of the area functional of the second fundamental form is given for a hypersurface in a semi-Riemannian space. The concept of the "mean curvatu…
Boost invariant marginally trapped surfaces in Minkowski 4-space
Stefan Haesen, Miguel Ortega
The extremal and partly marginally trapped surfaces in Minkowski 4-space, which are invariant under the group of boost isometries, are classified. Moreover, it is shown that there…
A new method to construct spacetimes with a spacelike circle action
Stefan Haesen, Francisco Palomo, Alfonso Romero
A new general procedure to construct realistic spacetimes is introduced. It is based on the null congruence on a time-oriented Lorentzian manifold associated to a certain timelike…