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The present study initially identify the generalized symmetric connections of type $(\alpha,\beta)$, which can be regarded as more generalized forms of quarter and semi-symmetric connections. The quarter and semi-symmetric connections are…

Differential Geometry · Mathematics 2020-10-02 Oğuzhan Bahadır , Sudhakar K Chaubey

In this paper, the notion of an almost contact K\"ahlerian structure is introduced. The interior geometry of almost contact K\"ahlerian spaces is investigated. On the zero-curvature distribution of an almost contact metric structure, as on…

Differential Geometry · Mathematics 2013-01-15 Sergey V. Galaev

Extending a result of He to the non-integrable case of K-contact manifolds, it is shown that transverse Hermitian scalar curvature may be interpreted as a moment map for the strict contactomorphism group. As a consequence, we may generalize…

Differential Geometry · Mathematics 2014-10-07 Mehdi Lejmi , Markus Upmeier

This paper is a survey of results obtained by the authors on the geometry of connections with totally skew-symmetric torsion on the following manifolds: almost complex manifolds with Norden metric, almost contact manifolds with B-metric and…

Differential Geometry · Mathematics 2012-03-27 Mancho Manev , Dimitar Mekerov , Kostadin Gribachev

In this article we study almost contact manifolds admitting weakly Einstein metrics. We first prove that if a (2n+1)-dimensional Sasakian manifold admits a weakly Einstein metric then its scalar curvature $s$ satisfies $-6\leqslant s…

Differential Geometry · Mathematics 2019-09-04 Xiaomin Chen

The main purpose of this work is to generalize the $S^3_\bfw$ Sasaki join construction $M\star_\bfl S^3_\bfw$ described in \cite{BoTo14a} when the Sasakian structure on $M$ is regular, to the general case where the Sasakian structure is…

Differential Geometry · Mathematics 2023-03-22 Charles P. Boyer , Christina W. Tønnesen-Friedman

We investigate the problem of approximating a regular Sasakian structure by CR immersions in a standard sphere. Namely, we show that this is always possible for compact Sasakian manifolds. Moreover, we prove an approximation result for…

Differential Geometry · Mathematics 2024-02-21 Giovanni Placini

In this article we study a class of normal{\theta}complex{\theta}contact{\theta}metric{\theta}manifold which is called a complex Sasakian manifold. This kind of manifold has a globally defined complex contact form and normal complex contact…

Differential Geometry · Mathematics 2021-01-05 Aysel Turgut Vanli , İnan Ünal , Keziban Avcu

We introduce higher order mean curvatures of screen almost conformal (SAC) half-lightlike submanifolds of indefinite contact manifolds, admitting a semi-symmetric non-metric connection, and use them to generalize some known results of [6].…

Differential Geometry · Mathematics 2016-10-25 Fortuné Massamba , Samuel Ssekajja

Under a pulled-back approach given in [1] and firstly presented in [2], we introduce, in this paper, the concepts of almost contact and normal almost contact Finsler structures on the pulled-back bundle. Properties of structures partly…

Differential Geometry · Mathematics 2016-06-22 Fortuné Massamba , Salomon Joseph Mbatakou

This paper introduces a new class of geometric structures in almost contact metric geometry, which we call locally conformal almost generalized $f$-cosymplectic manifolds. These are almost contact metric structures $(\phi, \xi, \eta, g)$…

Differential Geometry · Mathematics 2026-01-27 Fortuné Massamba , Jude Rosnick Bayeni Mitoueni

We study the question of the existence of left-invariant Sasaki contact structures on the seven-dimensional nilpotent Lie groups. It is shown that the only Lie group allowing Sasaki structure with a positive definite metric tensor is the…

Differential Geometry · Mathematics 2019-08-16 Nikolay K. Smolentsev

In this paper, we study and almost completely classify contact structures on closed 3--manifolds which are totally geodesic for some Riemannian metric. Due to previously known results, this amounts to classifying contact structures on…

Geometric Topology · Mathematics 2014-11-11 Patrick Massot

In this work, we prove that every complex contact structure gives rise to a distinguished type of almost contact metric 3-structure. As an application of our main result, we provide several new examples of manifolds which admit taut contact…

Differential Geometry · Mathematics 2020-09-24 Eder M. Correa

We consider an almost complex manifold with Norden metric (i. e. a metric with respect to which the almost complex structure is an anti-isometry). On such a manifold we study a linear connection preserving the almost complex structure and…

Differential Geometry · Mathematics 2011-01-24 Dimitar Mekerov

The paper observes an almost Hermitian manifold as an example of a generalized Riemannian manifold and examines the application of a quarter-symmetric connection on the almost Hermitian manifold. The almost Hermitian manifold with…

Differential Geometry · Mathematics 2024-01-15 Milan Zlatanović , Miroslav Maksimović

We interpret the property of having an infinitesimal symmetry as a variational property in certain geometric structures. This is achieved by establishing a one-to-one correspondence between a class of cone structures with an infinitesimal…

Differential Geometry · Mathematics 2026-04-03 Omid Makhmali , Katja Sagerschnig

Using the Sasakian join construction with homology 3-spheres, we give a countably infinite number of examples of Sasakian manifolds with perfect fundamental group in all odd dimensions greater than 1. These have extremal Sasaki metrics with…

Differential Geometry · Mathematics 2013-09-30 Charles P. Boyer , Christina W. Tønnesen-Friedman

For a finite family of 3-dimensional almost contact metric manifolds with closed the structure form $\eta$ is described a construction of an almost contact metric manifold, where the members of the family are building blocks - cells.…

Differential Geometry · Mathematics 2012-04-02 Piotr Dacko

We study almost contact metric structures induced by 2-fold vector cross products on manifolds with $G_2$ structures. We get some results on possible classes of almost contact metric structures. Finally we give examples.

Differential Geometry · Mathematics 2016-01-08 Nülifer Özdemir , Mehmet Solgun , Şirin Aktay