125 citations
Counting papers with at most 25 authors, so collaboration author lists do not stand in for the people here.
- Northern Border UniversitySA30 papers
- Centre National de la Recherche ScientifiqueFR16 papers
- Taibah UniversitySA16 papers
- Cairo UniversityEG12 papers
- Instituto de Astrofísica de AndalucíaES11 papers
- Université Paris CitéFR11 papers
- Astrophysique, Instrumentation et ModélisationFR10 papers
- Commissariat à l'Énergie Atomique et aux Énergies AlternativesFR10 papers
- Leibniz Institute for Astrophysics PotsdamDE10 papers
- Sorbonne UniversitéFR10 papers
- Astronomical ObservatoryRS9 papers
- CEA Paris-SaclayFR9 papers
6 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…
About influence of differential rotation in convection zone of gaseous or fluid giant Planet (Uranus) onto the parameters of orbits of satellites
Sergey V. Ershkov, Dmytro Leshchenko, Elbaz I. Abouelmagd
Tidal interactions between Planet and its satellites are known to be the main phenomena, which are determining the orbital evolution of the satellites. We suggest in the current re…
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…
Revisiting solving procedure for Ermakov-Pinney equation (with applications in the field of cosmology)
Sergey Ershkov, Victor Christianto, Elbaz I. Abouelmagd
It is known that Ermakov-Pinney equation is a nonlinear equation with wide applications in dynamics, physics, cosmology (e.g., Ermakov equation can be connected to Bose-Einstein Co…