English
Related papers

Related papers: (a, 1)f structures on product of spheres

200 papers

Choice of an appropriate (3+1)-foliation of spacetime or a (2+1)-foliation of the Cauchy space, leads often to a substantial simplification of various mathematical problems in General Relativity Theory. We propose a new method to construct…

General Relativity and Quantum Cosmology · Physics 2013-08-22 Hans-Peter Gittel , Jacek Jezierski , Jerzy Kijowski , Szymon Łȩski

We present natural families of coordinate algebras of noncommutative products of Euclidean spaces. These coordinate algebras are quadratic ones associated with an R-matrix which is involutive and satisfies the Yang-Baxter equations. As a…

Quantum Algebra · Mathematics 2018-05-23 Michel Dubois-Violette , Giovanni Landi

Lie groups considered as three-dimensional almost paracontact almost paracomplex Riemannian manifolds are investigated. In each basic class of the classification used for the manifolds under consideration, a correspondence is established…

Differential Geometry · Mathematics 2021-06-22 Mancho Manev , Veselina Tavkova

In this paper, we prove a classification theorem for the stable compact minimal submanifolds of the Riemannian product of an $m_1$-dimensional ($m_1\geq3$) hypersurface $M_1$ in the Euclidean space and any Riemannian manifold $M_2$, when…

Differential Geometry · Mathematics 2012-10-01 Hang Chen , Xianfeng Wang

It is introduced and studied para-Ricci-like solitons with potential Reeb vector field on almost paracontact almost paracomplex Riemannian manifolds. The special cases of para-Einstein-like, para-Sasaki-like and having a torse-forming Reeb…

General Mathematics · Mathematics 2023-09-06 Hristo Manev , Mancho Manev

Many authors have studied Ricci solitons and their analogs within the framework of (almost) contact geometry. In this article, we thoroughly study the $(m,\rho)$-quasi-Einstein structure on a contact metric manifold. First, we prove that if…

Differential Geometry · Mathematics 2020-10-30 Dhriti Sundar Patra , Vladimir Rovenski

We introduce the concept of $\varepsilon\,$-contact metric structures on oriented (pseudo-)Riemannian three-manifolds, which encompasses the usual Riemannian contact metric, Lorentzian contact metric and para-contact metric structures, but…

Differential Geometry · Mathematics 2022-10-13 Ángel Murcia

Motivated by the rich geometry of conformal Riemannian manifolds and by the recent development of geometries modeled on homogeneous spaces $G/P$ with $G$ semisimple and $P$ parabolic, Weyl structures and preferred connections are introduced…

Differential Geometry · Mathematics 2007-05-23 Andreas Cap , Jan Slovak

We build compact moduli spaces of Grassmannian framed bundles over a Riemann surface, essentially replacing a group by its bi-invariant compactification. We do this both in the algebraic and symplectic settings, and prove a…

Algebraic Geometry · Mathematics 2013-11-20 Usha Bhosle , Indranil Biswas , Jacques Hurtubise

We study 5-dimensional Riemannian manifolds that admit an almost contact metric structure. We classify these structures by their intrinsic torsion and review the literature in terms of this scheme. Moreover, we determine necessary and…

Differential Geometry · Mathematics 2012-11-13 Christof Puhle

We introduce generalized almost contact structures which admit the $B$-field transformations on odd dimensional manifolds. We provide definition of generalized Sasakain structures from the view point of the generalized almost contact…

Differential Geometry · Mathematics 2012-12-27 Ken'ichi Sekiya

The space of all non degenerate bilinear structures on a manifold $M$ carries a one parameter family of pseudo Riemannian metrics. We determine the geodesic equation, covariant derivative, curvature, and we solve the geodesic equation…

Differential Geometry · Mathematics 2016-09-06 Olga Gil-Medrano , Peter W. Michor , Martin Neuwirther

We show that, for any given $q\geq 0$, any Sasakian structure on a closed manifold $M$ is approximated in the $C^{q}$-norm by structures induced by CR embeddings into weighted Sasakian spheres. In order to obtain this result, we also…

Differential Geometry · Mathematics 2024-08-27 Andrea Loi , Giovanni Placini

Generalised spin structures, or r-spin structures, on a 2-dimensional orbifold \Sigma are r-fold fibrewise connected coverings (also called r-th roots) of its unit tangent bundle ST\Sigma. We investigate such structures on hyperbolic…

Geometric Topology · Mathematics 2012-08-29 Hansjörg Geiges , Jesús Gonzalo

Analogously to the concept of a curvature of curve and surface, in the differential geometry, in the main part of this paper the concept of the curvature of the hyper-dimensional vector spaces of Riemannian metric is generally defined. The…

Differential Geometry · Mathematics 2007-05-23 Branko Saric

We determine a 2-codimensional CR-structure on the slit tangent bundle $T_0M$ of a Finsler manifold $(M, F)$ by imposing a condition regarding the almost complex structure $\Psi$ associated to $F$ when restricted to the structural…

Differential Geometry · Mathematics 2016-08-11 Mircea Crasmareanu , Laurian-Ioan Pişcoran

We consider a $3$-dimensional differentiable manifold with two circulant structures -- a Riemannian metric and an additional structure, whose third power is the identity. The structure is compatible with the metric such that an isometry is…

Differential Geometry · Mathematics 2017-03-31 Georgi Dzhelepov

We show that, for each $n\ge 3$, there exists a smooth Riemannian metric $g$ on a punctured sphere $\mathbb{S}^n\setminus \{x_0\}$ for which the associated length metric extends to a length metric $d$ of $\mathbb{S}^n$ with the following…

Metric Geometry · Mathematics 2017-07-03 Pekka Pankka , Vyron Vellis

We provide a local classification of isometric immersions $f\colon L^p\times_\rho M^n\to\Q_c^{p+n+k}$ in codimensions $k=1, 2$ of warped products of Riemannian manifolds into space forms, under the assumptions that $n\geq k+1$ and that…

Differential Geometry · Mathematics 2007-05-23 M. Dajczer , R. Tojeiro

In this paper, we introduce semi-symmetric metric Koszul forms and semi-symmetric non-metric Koszul forms on singular semi-Riemannian manifolds. Semi-symmetric metric Koszul forms and semi-symmetric non-metric Koszul forms and their…

Differential Geometry · Mathematics 2021-06-02 Yong Wang