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We study harmonic almost contact structures in the context of contact metric manifolds, and an analysis is carried out when such a manifold fibres over an almost Hermitian manifold, as exemplified by the Boothby-Wang fibration. Two types of…

Differential Geometry · Mathematics 2007-09-03 E. Vergara-Diaz , C. M. Wood

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

This note is concerned in so called harmonic complex structures introduced by the author previously. I will recall some previous results and emphasize the motivation: Provide an attempt to a fundamental problem in geometry--determining the…

Differential Geometry · Mathematics 2016-10-27 Jianming Wan

Harmonicity of holomorphic maps between various subclasses of almost contact metric manifolds is discussed. Consequently, some new results are obtained. Also some known results are recovered, some of them are generalized and some of them…

Differential Geometry · Mathematics 2023-02-27 Sadettin Erdem

The study of harmonicity for almost contact metric structures was initiated by Vergara-D\'iaz and Wood and continued by Gonz\'alez-D\'avila and the present author. By using the intrinsic torsion and some restriction on the type of almost…

Differential Geometry · Mathematics 2019-07-05 Francisco Martín Cabrera

We consider normal almost contact structures on a Riemannian manifold and, through their associated sections of an ad-hoc twistor bundle, study their harmonicity, as sections or as maps. We rewrite these harmonicity equations in terms of…

Differential Geometry · Mathematics 2026-03-03 M. Benyounes , T. Levasseur , E. Loubeau , E. Vergara-Diaz

We consider normal almost contact structures on a Riemannian manifold and, through their associated sections of an ad-hoc twistor bundle, study their harmonicity, as sections or as maps. We rewrite these harmonicity equations in terms of…

Differential Geometry · Mathematics 2023-10-18 E. Loubeau , E. Vergara-Diaz

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

In this paper, we study metallic structures, i.e. polynomial structures with the structure polynomial $Q\left( J\right) =J^{2}-aJ-bI$ on manifolds using the metallic ratio, which is a generalization of the Golden proportion. We investigate…

Differential Geometry · Mathematics 2024-11-27 Mustafa Özkan , Fatma Yilmaz

We find geometric conditions on a four-dimensional almost Hermitian manifold under which the almost complex structure is a harmonic map or a minimal isometric imbedding of the manifold into its twistor space.

Differential Geometry · Mathematics 2017-11-15 Johann Davidov , Absar Ul Haq , Oleg Mushkarov

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

An almost Golden Riemannian structure $(\varphi ,g)$ on a manifold is given by a tensor field $\varphi $ of type (1,1) satisfying the Golden section relation $\varphi ^{2}=\varphi +1$, and a pure Riemannian metric $g$, i.e., a metric…

Differential Geometry · Mathematics 2017-10-19 Fernando Etayo , Rafael Santamaría , Abhitosh Upadhyay

Let (M, g) be a pseudo Riemannian manifold. We consider four geometric structures on M compatible with g: two almost complex and two almost product structures satisfying additionally certain integrability conditions. For instance, if r is a…

Differential Geometry · Mathematics 2015-11-19 Edison Alberto Fernández-Culma , Yamile Godoy , Marcos Salvai

The purpose of the present work is to study the complete and horizontal lifts of the metallic structure on tangent bundles with respect to almost product structure. We also establish fundamental formulae related to integrability and…

Differential Geometry · Mathematics 2018-10-16 Mohammad Nazrul Islam Khan

The concept of harmonic metallic structure on a metallic pseudo-Riemannian manifold is introduced. In the case of compact manifolds we prove that harmonicity of a metallic structure $J$, with $J^2=pJ+qI$ and $p^2+4q\neq 0$, is equivalent to…

Differential Geometry · Mathematics 2025-08-04 Adara M. Blaga , Antonella Nannicini

We consider principal fibre bundles with a given connection and construct almost complex structures on the total space if the adjoint bundle is isomorphic to the tangent bundle of the base. We derive the integrability condition. If the…

Differential Geometry · Mathematics 2017-02-15 Raphael Zentner

In this paper, metallic structure and almost quadratic metric phi-structure are studied. Based on metallic (polynomial) Riemannian manifold, Kenmotsu quadratic metric manifold, cosymplectic quadratic metric manifold are defined and gave…

General Mathematics · Mathematics 2018-12-31 Sinem Gönül , İrem Küpeli Erken , Aziz Yazla , Cengizhan Murathan

We obtain conditions on the Lee form under which a holomorphic map between almost Hermitian manifolds is a harmonic map or morphism. Then we discuss under what conditions (i) the image of a holomorphic map from a cosymplectic manifold is…

dg-ga · Mathematics 2008-02-03 S. Gudmundsson , J. C. Wood

In this paper, we study the existence of proper warped product submanifolds in metallic (or Golden) Riemannian manifolds and we discuss about semi-invariant, semi-slant and, respectively, hemi-slant warped product submanifolds in metallic…

Differential Geometry · Mathematics 2025-08-04 Cristina E. Hretcanu , Adara M. Blaga

This work is devoted to the study of the symmetries of (quasi)periodic architectured materials. For this purpose, the weaker symmetry criterion of indistinguishability is used. It relies on a statistical description of the mesostructure and…

Mathematical Physics · Physics 2026-04-03 Markus Hubert , Christelle Combescure , Renald Brenner , Nicolas Auffray
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