Results 41 to 50 of about 304,775 (175)

Invariant almost contact structure on the real extension of a sphere

open access: yesУчёные записки Казанского университета: Серия Физико-математические науки
The existence of contact and almost contact metric structures invariant under the group of motions on the real extension of a two-dimensional sphere with a Riemannian direct product metric was examined.
M. V. Sorokina, Y. V. Morshchinkina
doaj   +1 more source

Weak Quasi-Contact Metric Manifolds and New Characteristics of K-Contact and Sasakian Manifolds

open access: yesMathematics
Quasi-contact metric manifolds (introduced by Y. Tashiro and then studied by several authors) are a natural extension of contact metric manifolds. Weak almost-contact metric manifolds, i.e., where the linear complex structure on the contact distribution ...
Vladimir Rovenski
doaj   +1 more source

Matrix Lie groups as 3-dimensional almost contact B-metric manifolds [PDF]

open access: yes, 2015
The object of investigation are Lie groups considered as almost contact B-metric manifolds of the lowest dimension three. It is established a correspondence of all basic-class-manifolds of the Ganchev-Mihova-Gribachev classification of the studied ...
Manev, Hristo
core   +1 more source

Geometric structures on loop and path spaces

open access: yes, 2010
Is is known that the loop space associated to a Riemannian manifold admits a quasi-symplectic structure. This article shows that this structure is not likely to recover the underlying Riemannian metric by proving a result that is a strong indication of ...
A. Pressley   +6 more
core   +1 more source

A dimensional restriction for a class of contact manifolds

open access: yesDemonstratio Mathematica, 2017
In this work we consider a class of contact manifolds (M, η) with an associated almost contact metric Structure (ϕ, ξ, η, g). This class contains, for example, nearly cosymplectic manifolds and the manifolds in the class C9 ⊕ C10 defined by Chinea and ...
Loiudice Eugenia
doaj   +1 more source

On transversally elliptic operators and the quantization of manifolds with $f$-structure

open access: yes, 2011
An $f$-structure on a manifold $M$ is an endomorphism field $\phi\in\Gamma(M,\End(TM))$ such that $\phi^3+\phi=0$. Any $f$-structure $\phi$ determines an almost CR structure $E_{1,0}\subset T_\C M$ given by the $+i$-eigenbundle of $\phi$.
D. E. Blair   +15 more
core   +1 more source

Three-dimensional homogeneous almost contact metric structures

open access: yesJournal of Geometry and Physics, 2013
A manifold \(M^{2n+1}\) is said to be almost contact if its structure group can be reduced to \(\mathrm U(n)\). Equivalently, this means that \(M\) admits an almost contact structure, that is, a triple \((\varphi, \xi, \eta)\), where \(\varphi\) is a (1,1)-tensor, \(\xi\) a global vector field and \(\eta\) a 1-form, such that \(\varphi(\xi ) = 0 ...
openaire   +1 more source

Sewing cells in almost cosymplectic and almost Kenmotsu geometry [PDF]

open access: yes, 2012
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.
Dacko, Piotr
core  

Almost Contact Metric Structures Defined by a Symplectic Structure Over a Distribution

open access: yesIzvestiya of Saratov University. New Series. Series: Mathematics. Mechanics. Informatics, 2015
Summary: The distribution \(D\) of an almost contact metric structure \((\varphi, \vec \xi, \eta, g)\) is an odd analogue of the tangent bundle. In the paper an intrinsic symplectic structure naturally associated with the initial almost contact metric structure is constructed. The interior connection defines the parallel transport of admissible vectors
Galaev, S. V., Shevtsova, Yu. V.
openaire   +1 more source

On the geometry of generalized nonholonomic Kenmotsu manifolds

open access: yesДифференциальная геометрия многообразий фигур, 2022
The concept of a generalized nonholonomic Kenmotsu manifold is introduced. In contrast to the previously defined nonholonomic Kenmotsu manifold, the manifold studied in the article is an almost normal almost contact metric manifold of odd rank.
A.V. Bukusheva
doaj   +1 more source

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