Results 141 to 150 of about 106,337 (269)

A generalization of contact metric manifolds [PDF]

arXiv, 2013
We give a characterization of a contact metric manifold as a special almost contact metric manifold and discuss an almost contact metric manifold which is {a} natural generalization of the contact metric manifolds introduced by Y. Tashiro.
arxiv  

A Liouvile-type theorems for some classes of complete Riemannian almost product manifolds and for special mappings of complete Riemannian manifolds [PDF]

arXiv, 2016
In the present paper we prove Liouville-type theorems: non-existence theorems for some complete Riemannian almost product manifolds and special mappings of complete Riemannian manifolds which generalize similar results for compact manifolds.
arxiv  

Learning group invariant Calabi–Yau metrics by fundamental domain projections

Machine Learning: Science and Technology
We present new invariant machine learning models that approximate the Ricci-flat metric on Calabi–Yau (CY) manifolds with discrete symmetries. We accomplish this by combining state of the art models for predicting such metrics, based on the so-called φ ...
Yacoub Hendi, Magdalena Larfors, Moritz Walden   +2 more
doaj   +1 more source

Weakly holomorphic homogeneous regular manifolds [PDF]

arXiv
We introduce a class of complex manifolds which we call weakly holomorphic homogeneous regular manifolds (wHHR) manifolds. As the name suggests, this class contains the so-called holomorphic homogeneous regular manifolds but also other classes of complex manifolds such as two dimensional finite type domains and simply connected K\"ahler manifolds with ...
arxiv  

Three-dimensional Riemannian manifolds associated with locally conformal Riemannian product manifolds [PDF]

arXiv
A 3-dimensional Riemannian manifold equipped with a tensor structure of type $(1,1)$, whose fourth power is the identity, is considered. This structure acts as an isometry with respect to the metric. A Riemannian almost product manifold associated with such a manifold is also studied.
arxiv  

On a type of spacetime [PDF]

Mathematica Moravica, 2014
The object of the present paper is to study a special type of spacetime. It is proved that in a conformally flat (W RS)4 spacetime with non-zero scalar curvature the vector field p defined by ɡ(X, p) = E(X) is irrotational and the integral curves of the ...
Mallick Sahanous, Chand De Uday
doaj  

Non-zero degree maps between closed orientable three-manifolds [PDF]

arXiv, 2005
This paper adresses the following problem: Given a closed orientable three-manifold M, are there at most finitely many closed orientable three-manifolds 1-dominated by M? We solve this question for the class of closed orientable graph manifolds. More presisely the main result of this paper asserts that any closed orientable graph manifold 1-dominates ...
arxiv  

Essential constants for spatially homogeneous Ricci-flat manifolds of dimension 4+1 [PDF]

, 2004
T. Christodoulakis, Sigbjørn Hervik, G. Papadopoulos   +2 more
openalex   +1 more source

On Doubly Warped Product Finsler Manifolds [PDF]

arXiv, 2011
In this paper, we introduce horizontal and vertical warped product Finsler manifold. We prove that every C-reducible or proper Berwaldian doubly warped product Finsler manifold is Riemannian. Then, we find the relation between Riemmanian curvatures of doubly warped product Finsler manifold and its components, and consider the cases that this manifold ...
arxiv  

On the Optimal Control of Impulsive Hybrid Systems On Riemannian Manifolds [PDF]

arXiv, 2012
This paper provides a geometrical derivation of the Hybrid Minimum Principle (HMP) for autonomous impulsive hybrid systems on Riemannian manifolds, i.e. systems where the manifold valued component of the hybrid state trajectory may have a jump discontinuity when the discrete component changes value.
arxiv