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Almost contact structures can be identified with sections of a twistor bundle and this allows to define their harmonicity, as sections or maps. We consider the class of nearly cosymplectic almost contact structures on a Riemannian manifold…

Differential Geometry · Mathematics 2011-09-14 E. Loubeau , E. Vergara-Diaz

Weak almost contact manifolds, i.e., the linear complex structure on the contact distribution is replaced by a nonsingular skew-symmetric tensor, defined by the author and R. Wolak, allowed us to take a new look at the theory of contact…

Differential Geometry · Mathematics 2024-10-11 Vladimir Rovenski

The object of investigation are the almost contact manifolds with B-metric in the lowest dimension three, constructed on Lie algebras. It is considered a relation between the classes in the Bianchi classification of three-dimensional real…

Differential Geometry · Mathematics 2014-12-30 Hristo Manev

A Riemannian almost product manifold with integrable almost product structure is called a Riemannian product manifold. In the present paper the natural connections on such manifolds are studied, i.e. the linear connections preserving the…

Differential Geometry · Mathematics 2011-02-01 Dobrinka Gribacheva

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 a 3-dimensional Riemannian manifold V with a metric g and an affinor structure q. The local coordinates of these tensors are circulant matrices. In V we define an almost conformal transformation. Using that definition we…

Differential Geometry · Mathematics 2011-06-15 Georgi Dzhelepov , Dimitar Razpopov , Iva Dokuzova

This paper is a study of almost contact statistical manifolds. Especially this study is focused on almost cosymplectic statistical manifolds. We obtained basic properties of such manifolds. It is proved a characterization theorem and a…

Differential Geometry · Mathematics 2018-01-31 Aziz Yazla , İrem Küpeli Erken , Cengizhan Murathan

In this paper we construct and study almost paracontact metric structures $(\varphi ,\xi ,\eta ,g)$ on a 3-dimensional Walker manifold $(M,g)$ with respect to a local basis only by the coordinate functions of a unit space-like vector field…

Differential Geometry · Mathematics 2025-09-29 Galia Nakova , Cornelia-Livia Bejan

In this paper we generalize the main notions from the geometry of (almost) contact manifolds in the category of Lie algebroids. Also, using the framework of generalized geometry, we obtain an (almost) contact Riemannian Lie algebroid…

Differential Geometry · Mathematics 2016-11-14 Cristian Ida , Paul Popescu

There are introduced and studied a pair of associated Schouten-van Kampen affine connections adapted to the contact distribution and an almost contact B-metric structure generated by the pair of associated B-metrics and their Levi-Civita…

Differential Geometry · Mathematics 2015-12-23 Mancho Manev

In this paper we address what generalized geometric structures are possible on products of spaces that each admit generalized geometries. In particular we consider, first, the product of two odd dimensional spaces that each admit a…

Differential Geometry · Mathematics 2024-09-17 Ralph R. Gomez , Janet Talvacchia

The main purpose of the present paper is to define and study the notion of quasi bi-slant submanifolds of almost contact metric manifolds. We mainly concerned with quasi bi-slant submanifolds of cosymplectic manifolds as a generalization of…

General Mathematics · Mathematics 2020-03-10 Mehmet Akif Akyol , Selahattin Beyendi

We provide the first non-trivial examples of quasi-isometric embeddings between curve complexes. These are induced either by puncturing a closed surface or via orbifold coverings. As a corollary, we give new quasi-isometric embeddings…

Geometric Topology · Mathematics 2014-11-11 Kasra Rafi , Saul Schleimer

In this article, we study and analyze the \phi-sectional curvature induced by a statistical structure on an almost contact metric manifold. We demonstrate that this sectional curvature is always non-positive. Additionally, we present…

Differential Geometry · Mathematics 2025-07-02 Abbas Heydari , Sadegh Mohammadi

We give the necessary and sufficient conditions for the Penrose-Ward transformation to work on almost $G_2$-manifolds, endowed with natural almost twistorial structures.

Differential Geometry · Mathematics 2021-07-20 Radu Pantilie

An almost contact metric structure is parametrized by a section of an associated homogeneous fibre bundle, and conditions for this to be a harmonic section, and a harmonic map, are studied. These involve the characteristic vector field, and…

Differential Geometry · Mathematics 2007-05-23 E. Vergara-Diaz , C. M. Wood

The author is planning if possible classify all three-dimensional $(\kappa,\mu)$-manifolds wether contact metric, almost cosymplectic, para-contact metric, almost para-cosymplectic. Of course classification in contact or almost cosymplectic…

Differential Geometry · Mathematics 2020-06-30 Piotr Dacko

We consider manifolds endowed with a contact pair structure. To such a structure are naturally associated two almost complex structures. If they are both integrable, we call the structure a normal contact pair. We generalize the Morimoto's…

Differential Geometry · Mathematics 2009-06-20 G. Bande , A. Hadjar

We overview the properties of non-infinitesimal deformations of G2-structures on seven-manifolds, and in particular, focus on deformations that lie in the seven-dimensional representation of G2 and are thus defined by a vector. We then…

Differential Geometry · Mathematics 2013-01-22 Sergey Grigorian

We study nearly parallel $\mathrm{G}_{2}$-structures with a three-torus symmetry via multi-moment map techniques. An effective three-torus action on a nearly parallel $\mathrm{G}_{2}$-manifold yields a multi-moment map. The torus acts…

Differential Geometry · Mathematics 2026-05-18 Giovanni Russo , Andrew Swann