Results 31 to 40 of about 464 (128)

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

Geometric equations of state in Friedmann-Lema\^{i}tre universes admitting matter and Ricci Collineations

, 2003
As a rule in General Relativity the spacetime metric fixes the Einstein tensor and through the Field Equations (FE) the energy-momentum tensor. However one cannot write the FE explicitly until a class of observers has been considered.
Apostolopoulos, Pantelis S., Tsamparlis, Michael   +1 more
core   +1 more source

Curvature collineations for type-N Robinson-Trautman space-times [PDF]

General Relativity and Gravitation, 1983
The metric of type-N Robinson-Trautman space-times is generated by a real functionP satisfying certain field equations. Canonical forms forP are obtained under the assumption that at least one curvature collineation exists. In order to give an example of the improper subgroup structure of a group of curvature collineations all the curvature ...
Vaz, E. G. L. R., Collinson, C. D.
openaire   +3 more sources

2‐Conformal Vector Fields on the Model Sol Space and Hyperbolic Ricci Solitons

Journal of Mathematics, Volume 2025, Issue 1, 2025.
In this study, we present the notion of 2‐conformal vector fields on Riemannian and semi‐Riemannian manifolds, which are an extension of Killing and conformal vector fields. Next, we provide suitable vector fields in Sol space that are 2‐conformal. A few implications of 2‐conformal vector fields in hyperbolic Ricci solitons are investigated.
Rawan Bossly, Ghodratallah Fasihi-Ramandi, Mohd Danish Siddiqi, Antonio Masiello   +3 more
wiley   +1 more source

Paracomplex Paracontact Pseudo‐Riemannian Submersions

Geometry, Volume 2014, Issue 1, 2014., 2014
We introduce the notion of paracomplex paracontact pseudo‐Riemannian submersions from almost para‐Hermitian manifolds onto almost paracontact metric manifolds. We discuss the transference of structures on total manifolds and base manifolds and provide some examples.
S. S. Shukla, Uma Shankar Verma, Bennett Palmer   +2 more
wiley   +1 more source

Lie and Noether symmetries of geodesic equations and collineations

, 2011
The Lie symmetries of the geodesic equations in a Riemannian space are computed in terms of the special projective group and its degenerates (affine vectors, homothetic vector and Killing vectors) of the metric.
A. Barnes, A.H. Bokhari, A.H. Bokhari, A.V. Aminova, A.V. Aminova, A.V. Aminova, Andronikos Paliathanasis, G.E. Prince, G.H. Katzin, G.H. Katzin, G.H. Katzin, G.H. Katzin, H. Stephani, K. Yano, K.J.A. Scouten, M. Tsamparlis, M.S. Knebelman, Michael Tsamparlis, R. Maartens, R. Maartens, T. Feroze   +20 more
core   +1 more source

Multivariate Methods Based Soft Measurement for Wine Quality Evaluation

Abstract and Applied Analysis, Volume 2014, Issue 1, 2014., 2014
Soft measurement is a new, developing, and promising industry technology and has been widely used in the industry nowadays. This technology plays a significant role especially in the case where some key variables are difficult to be measured by traditional measurement methods.
Shen Yin, Lei Liu, Xin Gao, Hamid Reza Karimi, Josep M. Rossell   +4 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

Curvature collineations on Lie algebroid structure

, 2014
Considering prolongation of a Lie algebroid equipped with a spray, defining some classical tensors, we show that a Lie symmetry of a spray is a curvature collineation for these tensors.
Arcus, C. M., Peyghan, E., Sharahi, E.
openaire   +2 more sources

Special Recurrent Transformation in an NPR-Finsler Space

Cubo, 2012
In this paper, an infinitesimal transformation , where the vector vi is recurrent has been considered in an NPR- Finsler space. Such transformation is being called special recurrent transformation if the recurrence vector of the NPR- Finsler space is Lie
Anjali Goswami
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