نتایج جستجو برای: isotropic Weyl manifold

تعداد نتایج: 62444  

In this paper, we obtain a necessary and sufficient condition for a conformal mapping between two Weyl manifolds to preserve Einstein tensor. Then we prove that some basic curvature tensors of $W_n$ are preserved by such a conformal mapping if and only if the covector field of the mapping is locally a gradient. Also, we obtained the relation between the scalar curvatures of the Weyl manifolds r...

Journal: :bulletin of the iranian mathematical society 2015
m. gürlek g. çivi

in this paper, we obtain a necessary and sufficient condition for a conformal mapping between two weyl manifolds to preserve einstein tensor. then we prove that some basic curvature tensors of $w_n$ are preserved by such a conformal mapping if and only if the covector field of the mapping is locally a gradient. also, we obtained the relation between the scalar curvatures of the weyl manifolds r...

2012
ARASH YAVARI ALAIN GORIELY

The residual stress field of a nonlinear elastic solid with a spherically symmetric distribution of point defects is obtained explicitly using methods from differential geometry. The material manifold of a solid with distributed point defects—where the body is stress-free—is a flat Weyl manifold, i.e. a manifold with an affine connection that has non-metricity with vanishing traceless part, but...

ژورنال: پژوهش های ریاضی 2018

In this paper, Finsler metrics with relatively non-negative (resp. non-positive), isotropic and constant stretch curvature are studied.  In particular, it is showed that every compact Finsler manifold with relatively non-positive (resp. non-negative) stretch curvature is a Landsberg metric. Also, it is proved that every  (α,β)-metric of non-zero constant flag curvature and non-zero relatively i...

ژورنال: پژوهش های ریاضی 2021

In this paper, by using the concept of spherically symmetric metric, we defne the notion of λ-projectively related metrics as an extension of projectively related metrics. We construct some non-trivial examples of λ-projectively related metrics. Let F and G be two λ-projectively related metrics on a manifold M. We find the relation between the geodesics of F and G and prove that any geodesic of...

2008
R. A. Sharipov R. A. SHARIPOV

X iv :0 70 8. 11 71 v1 [ m at h. D G ] 8 A ug 2 00 7 ON THE SPINOR STRUCTURE OF THE HOMOGENEOUS AND ISOTROPIC UNIVERSE IN CLOSED MODEL. R. A. Sharipov Abstract. The closed homogeneous and isotropic universe is considered. The bundles of Weyl and Dirac spinors for this universe are explicitly described. Some explicit formulas for the basic fields and for the connection components in stereographi...

2009
FLORIN BELGUN ANDREI MOROIANU

A Weyl structure on a compact conformal manifold is not complete in general. If, however, the life-time of incomplete geodesics can be controlled on compact subsets of the tangent bundle, the Weyl connection is called tame. We prove that every closed, non-exact, tame Weyl structure on a compact conformal manifold is either flat, or has irreducible holonomy, generalizing an analogous statement f...

2004
John Miritzis

We study homogeneous and isotropic cosmologies in a Weyl spacetime. We show that for homogeneous and isotropic spacetimes, the field equations can be reduced to the Einstein equations with a twofluid source. We write the equations as a two-dimensional dynamical system and analyze the qualitative, asymptotic behavior of the models. We examine the possibility that in certain theories the Weyl 1-f...

2013
S. KAZAN

In this paper, we give characterizations of a twisted product manifold to be a warped product manifold by imposing certain conditions on the Weyl conformal curvature tensor and the Weyl projective tensor. We also find similar results for multiply twisted product manifolds.

2005
LIANA DAVID

We introduce and study the notion of Sasaki–Weyl manifold, which is a natural generalization of the notion of Sasaki manifold. We construct a reduction of Sasaki–Weyl manifolds and we show that it commutes with several reductions already existing in the literature.

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