scholarly journals On a Riemannian manifold with a circulant structure whose third power is the identity

Filomat ◽  
2018 ◽  
Vol 32 (10) ◽  
pp. 3529-3539 ◽  
Author(s):  
Iva Dokuzova
Keyword(s):  
Riemannian Manifold ◽  
Lie Group ◽  
Covariant Derivative ◽  
Conformal Transformation ◽  
Circulant Matrix ◽  
Tensor Structure ◽  
Fundamental Tensor ◽  
3 Dimensional ◽  
Geometrical Characteristics

It is studied a 3-dimensional Riemannian manifold equipped with a tensor structure of type (1,1), whose third power is the identity. This structure has a circulant matrix with respect to some basis, i.e. the structure is circulant. On such a manifold a fundamental tensor by the metric and by the covariant derivative of the circulant structure is defined. An important characteristic identity for this tensor is obtained. It is established that the image of the fundamental tensor with respect to the usual conformal transformation satisfies the same identity. A Lie group as a manifold of the considered type is constructed and some of its geometrical characteristics are found.

scholarly journals Correction: Çakmak, A. New Type Direction Curves in 3-Dimensional Compact Lie Group Symmetry 2019, 11, 387

Symmetry ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 284
Author(s):  
Ali Çakmak
Keyword(s):  
Lie Group ◽  
Group Symmetry ◽  
Compact Lie Group ◽  
3 Dimensional ◽  
New Type ◽  
Lie Group Symmetry

The authors wish to make the following corrections to their paper [...]

On Conformally Flat Spaces with Commuting Curvature and Ricci Transformations

1972 ◽  
Vol 24 (5) ◽  
pp. 799-804 ◽  
Author(s):  
R. L. Bishop ◽  
S.I. Goldberg
Keyword(s):  
Riemannian Manifold ◽  
Covariant Derivative ◽  
Ricci Tensor ◽  
Vector Fields ◽  
Conformally Flat ◽  
Image Position

Let (M, g) be a C∞ Riemannian manifold and A be the field of symmetric endomorphisms corresponding to the Ricci tensor S; that is,We consider a condition weaker than the requirement that A be parallel (▽ A = 0), namely, that the “second exterior covariant derivative” vanish ( ▽x▽YA — ▽Y ▽XA — ▽[X,Y]A = 0), which by the classical interchange formula reduces to the propertywhere R(X, Y) is the curvature transformation determined by the vector fields X and Y.The property (P) is equivalent toTo see this we observe first that a skew symmetric and a symmetric endomorphism commute if and only if their product is skew symmetric.

scholarly journals Submanifolds and the length of the second fundamental tensor

1983 ◽  
Vol 34 (1) ◽  
pp. 1-6
Author(s):  
Thomas Hasanis
Keyword(s):  
Riemannian Manifold ◽  
Constant Curvature ◽  
Positive Constant ◽  
Mean Curvature ◽  
Sufficient Condition ◽  
Fundamental Tensor ◽  
The Mean

AbstractA sufficient condition, for a complete submanifold of a Riemannian manifold of positive constant curvature to be umbilical, is given. The condition will be given by an inequality which is established between the length of the second fundamental tensor and the mean curvature.

scholarly journals Almost Positive Curvature on an Irreducible Compact Rank 2 Symmetric Space

2018 ◽  
Vol 2020 (5) ◽  
pp. 1346-1365 ◽  
Author(s):  
Jason DeVito ◽  
Ezra Nance
Keyword(s):  
Riemannian Manifold ◽  
Symmetric Space ◽  
Sectional Curvature ◽  
Lie Group ◽  
Positive Curvature ◽  
Positive Sectional Curvature ◽  
Compact Symmetric Space ◽  
Rank 2 ◽  
Set Of Points ◽  
Positively Curved

Abstract A Riemannian manifold is said to be almost positively curved if the set of points for which all two-planes have positive sectional curvature is open and dense. We show that the Grassmannian of oriented two-planes in $\mathbb{R}^{7}$ admits a metric of almost positive curvature, giving the first example of an almost positively curved metric on an irreducible compact symmetric space of rank greater than 1. The construction and verification rely on the Lie group $\mathbf{G}_{2}$ and the octonions, so do not obviously generalize to any other Grassmannians.

scholarly journals On a class of exact locally conformal cosymlectic manifolds

1996 ◽  
Vol 19 (2) ◽  
pp. 267-278
Author(s):  
I. Mihai ◽  
L. Verstraelen ◽  
R. Rosca
Keyword(s):  
Riemannian Manifold ◽  
Vector Field ◽  
Conformal Transformation ◽  
Space Form ◽  
Conformal Vector Field ◽  
Cosymplectic Manifold ◽  
Almost Cosymplectic Manifold ◽  
Riemannian Connection ◽  
Locally Conformal ◽  
Hyperbolic Space Form

An almost cosymplectic manifoldMis a(2m+1)-dimensional oriented Riemannian manifold endowed with a 2-formΩof rank2m, a 1-formηsuch thatΩm Λ η≠0and a vector fieldξsatisfyingiξΩ=0andη(ξ)=1. Particular cases were considered in [3] and [6].Let(M,g)be an odd dimensional oriented Riemannian manifold carrying a globally defined vector fieldTsuch that the Riemannian connection is parallel with respect toT. It is shown that in this caseMis a hyperbolic space form endowed with an exact locally conformal cosymplectic structure. MoreoverTdefines an infinitesimal homothety of the connection forms and a relative infinitesimal conformal transformation of the curvature forms.The existence of a structure conformal vector fieldConMis proved and their properties are investigated. In the last section, we study the geometry of the tangent bundle of an exact locally conformal cosymplectic manifold.

scholarly journals Lie Supergroups Obtained from 3-Dimensional Lie Superalgebras Associated to the Adjoint Representation and Having a 2-Dimensional Derived Ideal

2008 ◽  
Vol 2008 ◽  
pp. 1-9
Author(s):  
I. Hernández ◽  
R. Peniche
Keyword(s):  
Lie Group ◽  
Lie Superalgebra ◽  
Adjoint Representation ◽  
Lie Superalgebras ◽  
Base Manifold ◽  
3 Dimensional ◽  
Lie Supergroups

We give the explicit multiplication law of the Lie supergroups for which the base manifold is a 3-dimensional Lie group and whose underlying Lie superalgebrag=g0⊕g1which satisfiesg1=g0,g0acts ong1via the adjoint representation andg0has a 2-dimensional derived ideal.

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