Results 41 to 50 of about 507 (127)
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 +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 +2 more
wiley +1 more source
Special concircular projective curvature collineation in recurrent Finsler space
, 2012 Surya Prakash Singh
openalex +3 more sources
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 +4 more
wiley +1 more source
, 2001 Models with a dynamic cosmological term \Lambda (t) are becoming popular as they solve the cosmological constant problem in a natural way. Instead of considering any ad-hoc assumption for the variation of \Lambda, we consider a particular symmetry, the ...
Vishwakarma, R. G.
core +2 more sources
Comment on Ricci Collineations of Static Spherically Symmetric Spacetimes [PDF]
, 1994 We present a counter example to a theorem given by Amir {\em et al.} J. Math. Phys. {\bf 35}, 3005 (1994).
G. Contreras +6 more
core +3 more sources
f(R, ϕ) and f(R) Models: A Self‐Similar Approach
Journal of Mathematics, Volume 2013, Issue 1, 2013., 2013 We study the f(R, ϕ) models and their particular case, the so‐called f(R)‐models under the self‐similarity hypothesis. In particular, we calculate the exact form that each quantity may take in order that field equations (FEs) admit self‐similar solutions. The methods employed allow us to obtain general results that are valid not only for the FRW metric,
José Antonio Belinchón, Jianming Zhan
wiley +1 more source
Two dimensional dynamical systems which admit Lie and Noether symmetries
, 2011 We prove two theorems which relate the Lie point symmetries and the Noether symmetries of a dynamical system moving in a Riemannian space with the special projective group and the homothetic group of the space respectively.
Aminova A V +12 more
core +1 more source
Collineations of a symmetric 2-covariant tensor: Ricci collineations [PDF]
, 2013 The infinitesimal transformations that leave invariant a two-covariant symmetric tensor are studied. The interest of these symmetry transformations lays in the fact that this class of tensors includes the energy-momentum and Ricci tensors.
Llosa, Josep
core +3 more sources
On the general structure of Ricci collineations for type B warped spacetimes
, 2004 A complete study of the structure of Ricci collineations for type B warped spacetimes is carried out. This study can be used as a method to obtain these symetries in such spacetimes.
Apostolopoulos P. S. +10 more
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