Results 31 to 40 of about 507 (127)

Ricci Collineations for type B warped space-times [PDF]

, 1997
We present the general structure of proper Ricci Collineations (RC) for type B warped space-times. Within this framework, we give a detailed description of the most general proper RC for spherically symmetric metrics.
A. A. Coley, A. H. Bokhari, A. Melfo, A. Melfo, B. Haddow, D. Kramer, D. R. Oliver, G. H. Katzin, G. S. Hall, G. S. Hall, J. Carot, J. Carot, J. Carot, K. L. Duggal, L. A. Núñez, L. Aulestia, L. H. Green, L. Núñez, M. Jamil Amir, M. L. Bedran, M. Tsamparlis, P. Aichelburg, R. Bertolotti, S. Hojman, S. Weinberg, T. B. Farid, U. Percoco   +26 more
core   +2 more sources

Geometrical/Physical Interpretation of the Conserved Quantities Corresponding to Noether Symmetries of Plane Symmetric Space‐Times

Advances in Mathematical Physics, Volume 2017, Issue 1, 2017., 2017
The aim of this paper is to give the geometrical/physical interpretation of the conserved quantities corresponding to each Noether symmetry of the geodetic Lagrangian of plane symmetric space‐times. For this purpose, we present a complete list of plane symmetric nonstatic space‐times along with the generators of all Noether symmetries of the geodetic ...
Bismah Jamil, Tooba Feroze, Andrés Vargas, Igor L. Freire   +3 more
wiley   +1 more source

symmetries of the Ricci tensor of static space times with maximal symmetric transverse spaces

, 2006
Static space times with maximal symmetric transverse spaces are classified according to their Ricci collineations. These are investigated for non-degenerate Ricci tensor ($det.(R_{\alpha}) \neq 0$).
A.Z. Petro, Cai Rong-Gen, G.H. Katzin, G.H. Katzin, M Akbar   +4 more
core   +2 more sources

Features from a Single Vector Pressure Stroke

Mathematical Problems in Engineering, Volume 2017, Issue 1, 2017., 2017
Freehand sketching in a real‐time 3D styling system presents a different way to create a 3D model from the traditional CAD system. Strokes are the most common and useful objects in the expression of a stylist’s intention by using the gesture commands and in the construction of geometries.
Qiang Li, Changhai Yang, Zhao Zhang, Xi Wang, Yongjian Gong, Cuixian Xuan, Chaudry M. Khalique   +6 more
wiley   +1 more source

Relativistic Localizing Processes Bespeak an Inevitable Projective Geometry of Spacetime

Advances in High Energy Physics, Volume 2017, Issue 1, 2017., 2017
Surprisingly, the issue of events localization in spacetime is poorly understood and a fortiori realized even in the context of Einstein’s relativity. Accordingly, a comparison between observational data and theoretical expectations might then be strongly compromised. In the present paper, we give the principles of relativistic localizing systems so as
Jacques L. Rubin, Ralf Hofmann
wiley   +1 more source

Spacelike Ricci Inheritance Vectors in a Model of String Cloud and String Fluid Stress Tensor

, 2005
We study the consequences of the existence of spacelike Ricci inheritance vectors (SpRIVs) parallel to $x^a$ for model of string cloud and string fluid stress tensor in the context of general relativity.
Carot J, Collinson C D, Duggal K L, Greenberg P S, H sn  Baysal, Ihsan Yilmaz, Katzin G H, Kibble T W S, Letelier P S, Zeldovich Ya B   +9 more
core   +1 more source

Symmetries of the Energy-Momentum Tensor: Some Basic Facts [PDF]

, 2006
It has been pointed by Hall et al. [1] that matter collinations can be defined by using three different methods. But there arises the question of whether one studies matter collineations by using the ${\cal L}_\xi T_{ab}=0$, or ${\cal L}_\xi T^{ab}=0$ or
E. Noether, G.S. Hall, G.S. Hall, J. Carot, J. Ehlers, M Sharif, Sehar Aziz, Tariq Ismaeel, Tariq Ismaeel, U. Camci   +9 more
core   +3 more sources

Non‐Perfect‐Fluid Space‐Times in Thermodynamic Equilibrium and Generalized Friedmann Equations

Journal of Gravity, Volume 2016, Issue 1, 2016., 2016
We determine the energy‐momentum tensor of nonperfect fluids in thermodynamic equilibrium and, respectively, near to it. To this end, we derive the constitutive equations for energy density and isotropic and anisotropic pressure as well as for heat‐flux from the corresponding propagation equations and by drawing on Einstein’s equations.
Konrad Schatz, Horst-Heino von Borzeszkowski, Thoralf Chrobok, Sergei D. Odintsov   +3 more
wiley   +1 more source

On Quasi‐Hermitian Varieties in Even Characteristic and Related Orthogonal Arrays

Journal of Combinatorial Designs, Volume 33, Issue 3, Page 109-122, March 2025.
ABSTRACT In this article, we study the BM quasi‐Hermitian varieties, laying in the three‐dimensional Desarguesian projective space of even order. After a brief investigation of their combinatorial properties, we first show that all of these varieties are projectively equivalent, exhibiting a behavior which is strikingly different from what happens in ...
Angela Aguglia, Luca Giuzzi, Alessandro Montinaro, Viola Siconolfi   +3 more
wiley   +1 more source

Concircular vector fields for Kantowski Sachs and Bianchi type III spacetimes

, 2017
This paper intends to obtain concircular vector fields of Kantowski Sachs and Bianch type III spacetimes. For this purpose, ten conformal Killing equations and their general solution in the form of conformal Killing vector fields are derived along with ...
Ali, Ahmad T, Khan, Suhail, Mahmood, Amjad   +2 more
core   +1 more source