124 citations · 418 across the 27 of their papers we have counts for
5 papers · 1 filter
A new topological perspective of expanding space-times with applications to cosmology
Nasr Ahmed, Anirudh Pradhan, F. Salama
We discuss the possible role of the Tietze extension theorem in providing a rigorous topological base to the expanding space-time in cosmology. A simple toy model has been introduc…
Space-time singularities and the theory of retracts
Nasr Ahmed, H. Rafat
In previous publications, we have started investigating some possible applications to the retraction theory in gravitational physics and showed that it can be very useful in provid…
On the existence of deformations and dimensional reduction in wormholes and black holes
Nasr Ahmed, H. Rafat
The deformation retract is, by definition, a homotopy between a retraction and the identity map. We show that applying this topological concept to Ricci-flat wormholes/black holes…
Deformation Retract and Folding of the 5D Schwarzchild Field
Nasr Ahmed, H. Rafat
In this article we introduce some types of the deformtion retracts of the Schwarzchild space making use of Lagrangian equations. The retraction of this space into itself and i…
Bianchi Type- cosmology in gravity with
Nasr Ahmed, Anirudh Pradhan
A new class of cosmological models in modified theories of gravity proposed by Harko et al. (2011), where the gravitational Lagrangian is given by an arbitrary function o…