scholarly journals $W_{2}$-CURVATURE TENSOR ON K-CONTACT MANIFOLDS

2021 ◽  
pp. 995
Author(s):  
Krishnendu De
Keyword(s):  
Curvature Tensor ◽  
Sufficient Conditions ◽  
Contact Manifold ◽  
Sasakian Manifold ◽  
Contact Manifolds

The object of the present paper is to obtain sufficient conditions  for a K-contact manifold to be a Sasakian manifold.

scholarly journals Hypersurfaces of Lorentzian para-Sasakian manifolds

2011 ◽  
Vol 109 (1) ◽  
pp. 5 ◽  
Author(s):  
Selcen Yüksel Perktas ◽  
Erol Kiliç ◽  
Sadik Keles
Keyword(s):  
Sufficient Conditions ◽  
Contact Manifold ◽  
Sasakian Manifold ◽  
Product Structure ◽  
Product Manifold ◽  
Sasakian Manifolds ◽  
Contact Manifolds ◽  
Sasakian Structure ◽  
Almost Contact Manifold ◽  
Necessary And Sufficient

In this paper we study the invariant and noninvariant hypersurfaces of $(1,1,1)$ almost contact manifolds, Lorentzian almost paracontact manifolds and Lorentzian para-Sasakian manifolds, respectively. We show that a noninvariant hypersurface of an $(1,1,1)$ almost contact manifold admits an almost product structure. We investigate hypersurfaces of affinely cosymplectic and normal $(1,1,1)$ almost contact manifolds. It is proved that a noninvariant hypersurface of a Lorentzian almost paracontact manifold is an almost product metric manifold. Some necessary and sufficient conditions have been given for a noninvariant hypersurface of a Lorentzian para-Sasakian manifold to be locally product manifold. We establish a Lorentzian para-Sasakian structure for an invariant hypersurface of a Lorentzian para-Sasakian manifold. Finally we give some examples for invariant and noninvariant hypersurfaces of a Lorentzian para-Sasakian manifold.

scholarly journals Metric f-Contact Manifolds Satisfying the (κ, μ)-Nullity Condition

Mathematics ◽  
2020 ◽  
Vol 8 (6) ◽  
pp. 891
Author(s):  
Alfonso Carriazo ◽  
Luis M. Fernández ◽  
Eugenia Loiudice
Keyword(s):  
Explicit Expression ◽  
Sectional Curvature ◽  
Curvature Tensor ◽  
Tensor Field ◽  
Contact Manifold ◽  
Contact Manifolds

We prove that if the f-sectional curvature at any point of a ( 2 n + s ) -dimensional metric f-contact manifold satisfying the ( κ , μ ) nullity condition with n > 1 is independent of the f-section at the point, then it is constant on the manifold. Moreover, we also prove that a non-normal metric f-contact manifold satisfying the ( κ , μ ) nullity condition is of constant f-sectional curvature if and only if μ = κ + 1 and we give an explicit expression for the curvature tensor field in such a case. Finally, we present some examples.

scholarly journals On W0 and W2 ø-Symmetric Contact Manifold Admitting Quarter-Symmetric Metric Connection

2021 ◽  
Vol 2070 (1) ◽  
pp. 012075
Author(s):  
K. T. Pradeep Kumar ◽  
B.M. Roopa ◽  
K.H. Arun Kumar
Keyword(s):  
Curvature Tensor ◽  
Contact Manifold ◽  
Contact Manifolds ◽  
Metric Connection

Abstract The paper deals locally W0 and W2 curvature tensor of ø-symmetric K-contact manifolds with quarter-symmetric metric connection and some results are obtained.

scholarly journals A NATURAL CONNECTION ON A BASIC CLASS OF RIEMANNIAN PRODUCT MANIFOLDS

2012 ◽  
Vol 09 (07) ◽  
pp. 1250057 ◽  
Author(s):  
DOBRINKA GRIBACHEVA
Keyword(s):  
Curvature Tensor ◽  
Sufficient Conditions ◽  
Flat Connection ◽  
Riemannian Product ◽  
Natural Connection ◽  
Hermitian Geometry ◽  
Locally Conformal Kähler ◽  
Basic Class ◽  
Necessary And Sufficient ◽  
Locally Conformal

A Riemannian manifold M with an integrable almost product structure P is called a Riemannian product manifold. Our investigations are on the manifolds (M, P, g) of the largest class of Riemannian product manifolds, which is closed with respect to the group of conformal transformations of the metric g. This class is an analogue of the class of locally conformal Kähler manifolds in almost Hermitian geometry. In the present paper we study a natural connection D on (M, P, g) (i.e. DP = Dg = 0). We find necessary and sufficient conditions, the curvature tensor of D to have properties similar to the Kähler tensor in Hermitian geometry. We pay attention to the case when D has a parallel torsion. We establish that the Weyl tensors for the connection D and the Levi-Civita connection coincide as well as the invariance of the curvature tensor of D with respect to the usual conformal transformation. We consider the case when D is a flat connection. We construct an example of the considered manifold by a Lie group where D is a flat connection with non-parallel torsion.

scholarly journals Open books and exact symplectic cobordisms

2018 ◽  
Vol 29 (04) ◽  
pp. 1850026 ◽  
Author(s):  
Mirko Klukas
Keyword(s):  
Disjoint Union ◽  
Contact Manifold ◽  
Higher Dimensions ◽  
Fiber Bundles ◽  
Open Book ◽  
Contact Manifolds ◽  
Open Books ◽  
Symplectic Cobordism ◽  
The Given ◽  
Symplectic Cobordisms

Given two open books with equal pages, we show the existence of an exact symplectic cobordism whose negative end equals the disjoint union of the contact manifolds associated to the given open books, and whose positive end induces the contact manifold associated to the open book with the same page and concatenated monodromy. Using similar methods, we show the existence of strong fillings for contact manifolds associated with doubled open books, a certain class of fiber bundles over the circle obtained by performing the binding sum of two open books with equal pages and inverse monodromies. From this we conclude, following an outline by Wendl, that the complement of the binding of an open book cannot contain any local filling obstruction. Given a contact [Formula: see text]-manifold, according to Eliashberg there is a symplectic cobordism to a fibration over the circle with symplectic fibers. We extend this result to higher dimensions recovering a recent result by Dörner–Geiges–Zehmisch. Our cobordisms can also be thought of as the result of the attachment of a generalized symplectic [Formula: see text]-handle.

scholarly journals NATURAL CONNECTION WITH TOTALLY SKEW-SYMMETRIC TORSION ON ALMOST CONTACT MANIFOLDS WITH B-METRIC

2012 ◽  
Vol 09 (05) ◽  
pp. 1250044 ◽  
Author(s):  
MANCHO MANEV
Keyword(s):  
Curvature Tensor ◽  
Torsion Tensor ◽  
Contact Manifolds ◽  
Natural Connection ◽  
Civita Connection ◽  
Levi Civita Connection

A natural connection with totally skew-symmetric torsion on almost contact manifolds with B-metric is constructed. The class of these manifolds, where the considered connection exists, is determined. Some curvature properties for this connection, when the corresponding curvature tensor has the properties of the curvature tensor for the Levi-Civita connection and the torsion tensor is parallel, are obtained.

scholarly journals Certain results on generalized (k,\mu)-contact manifolds

2017 ◽  
Vol 37 (3) ◽  
pp. 131
Author(s):  
Pradip Majhi ◽  
Gopal Ghosh
Keyword(s):  
Contact Manifold ◽  
Contact Manifolds

The object of the present paper is to study generalized (k,\mu)-contact manifolds. At first we consider \phi-semisymmetric generalized (k,\mu)-contact manifolds. Beside these we study extended pseudo projective at generalized (k,\mu)-contact manifolds. Also (k,\mu )-contact manifold satisfying \barP^e.S = 0 is also considered. As a consequence we obtain several corollaries.

scholarly journals Space time manifolds and contact structures

1990 ◽  
Vol 13 (3) ◽  
pp. 545-553 ◽  
Author(s):  
K. L. Duggal
Keyword(s):  
Contact Structure ◽  
Contact Manifold ◽  
Contact Structures ◽  
Timelike Vector ◽  
Contact Manifolds ◽  
New Class ◽  
Dimensional Spacetime ◽  
Globally Hyperbolic Spacetimes ◽  
Hyperbolic Spacetimes ◽  
Regular Contact

A new class of contact manifolds (carring a global non-vanishing timelike vector field) is introduced to establish a relation between spacetime manifolds and contact structures. We show that odd dimensional strongly causal (in particular, globally hyperbolic) spacetimes can carry a regular contact structure. As examples, we present a causal spacetime with a non regular contact structure and a physical model [Gödel Universe] of Homogeneous contact manifold. Finally, we construct a model of 4-dimensional spacetime of general relativity as a contact CR-submanifold.

scholarly journals Para-CR structures on almost paracontact metric manifolds

2014 ◽  
Vol 20 (2) ◽  
Author(s):  
Joanna Wełyczko
Keyword(s):  
Sectional Curvature ◽  
Sufficient Conditions ◽  
Sasakian Manifold ◽  
Necessary And Sufficient Conditions ◽  
Constant Sectional Curvature ◽  
Conformally Flat ◽  
Cr Manifolds ◽  
Cosymplectic Manifolds ◽  
Cr Structures ◽  
Necessary And Sufficient

AbstractAlmost paracontact metric manifolds are the famous examples of almost para-CR manifolds. We find necessary and sufficient conditions for such manifolds to be para-CR. Next we examine these conditions in certain subclasses of almost paracontact metric manifolds. Especially, it is shown that normal almost paracontact metric manifolds are para-CR. We establish necessary and sufficient conditions for paracontact metric manifolds as well as for almost para-cosymplectic manifolds to be para-CR. We find also basic curvature identities for para-CR paracontact metric manifolds and study their consequences. Among others, we prove that any para-CR paracontact metric manifold of constant sectional curvature and of dimension greater than 3 must be para-Sasakian and its curvature equal to -1. The last assertion does not hold in dimension 3. We show that a conformally flat para-Sasakian manifold is of constant sectional curvature equal to -1. New classes of examples of para-CR manifolds are established.

scholarly journals Translated points on hypertight contact manifolds

2018 ◽  
Vol 10 (02) ◽  
pp. 289-322
Author(s):  
Matthias Meiwes ◽  
Kathrin Naef
Keyword(s):  
Floer Homology ◽  
Contact Manifold ◽  
Contact Form ◽  
Contact Manifolds ◽  
Rabinowitz Floer Homology

A contact manifold admitting a supporting contact form without contractible Reeb orbits is called hypertight. In this paper we construct a Rabinowitz–Floer homology associated to an arbitrary supporting contact form for a hypertight contact manifold [Formula: see text], and use this to prove versions of a conjecture of Sandon [17] on the existence of translated points and to show that positive loops of contactomorphisms give rise to non-contractible Reeb orbits.

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