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For curves singularities the dimension of smoothing components in the deformation space is an invariant of the singularity, but in general the deformation space has components of different dimensions. We are interested in the question what…

代数几何 · 数学 2025-04-02 Jan Stevens

We study general relativity in the framework of non-commutative differential geometry. In particular, we introduce a gravity action for a space-time which is the product of a four dimensional manifold by a two-point space. In the simplest…

高能物理 - 理论 · 物理学 2008-11-26 A. H. Chamseddine , G. Felder , J. Fröhlich

It is proved that every locally conformal flat Riemannian manifold all of whose Jacobi operators have constant eigenvalues along every geodesic is with constant principal Ricci curvatures. A local classification (up to an isometry) of…

dg-ga · 数学 2008-02-03 Stefan Ivanov , Irina Petrova

We give the classification of constant mean curvature rotational surfaces of elliptic, hyperbolic, and parabolic type in the four-dimensional pseudo-Euclidean space with neutral metric.

微分几何 · 数学 2016-03-03 Yana Aleksieva , Velichka Milousheva

We study expansion/contraction properties of some common classes of mappings of the Euclidean space ${\mathbb R}^n, n\ge 2\,,$ with respect to the distance ratio metric. The first main case is the behavior of M\"obius transformations of the…

复变函数 · 数学 2013-07-11 Slavko Simić , Matti Vuorinen , Gendi Wang

A rigidity result for a class of compact generalized quasi-Einstein manifolds with constant scalar curvature is obtained. Moreover, under some geometric assumptions, the rigidity for the noncompact case is also proved. Considering non…

微分几何 · 数学 2021-12-09 Antonio Airton Freitas Filho , Keti Tenenblat

We characteristize those Einstein four manifolds which are locally symmetric spaces of noncompact type. Namely they are four manifolds which admit solutions to the (non-Abelian) Seiberg Witten equations and satisty certain characterisitc…

dg-ga · 数学 2008-02-03 Naichung Conan Leung

In this paper, we study generalized constant ratio (GCR) hypersurfaces in Euclidean spaces. We mainly focus on the hypersurfaces in $\mathbb E^4$. First, we deal with $\delta(2)$-ideal GCR hypersurfaces. Then, we study on hypersurfaces with…

微分几何 · 数学 2015-04-30 Nurettin Cenk Turgay

We study the boundedness of intrinsic square functions and their commutators on generalized Orlicz-Morrey spaces $M^{\Phi,\varphi}(\mathbb{R}^n)$. In all the cases the conditions for the boundedness are given either in terms of Zygmund-type…

泛函分析 · 数学 2013-11-27 Vagif S. Guliyev , Fatih Deringoz

We review recent progress in the study of varying constants and attempts to explain the observed values of the fundamental physical constants. We describe the variation of $G$ in Newtonian and relativistic scalar-tensor gravity theories. We…

广义相对论与量子宇宙学 · 物理学 2009-09-25 John D. Barrow

The article delivers the only still unknown coefficient in the 4th post-Newtonian energy expression for binary point masses on circular orbits as function of orbital angular frequency. Apart from a single coefficient, which is known solely…

广义相对论与量子宇宙学 · 物理学 2013-05-01 Piotr Jaranowski , Gerhard Schäfer

We consider non-linear gravitational models with a multidimensional warped product geometry. Particular attention is payed to models with quadratic scalar curvature terms. It is shown that for certain parameter ranges, the extra dimensions…

高能物理 - 理论 · 物理学 2014-11-18 U. Guenther , P. Moniz , A. Zhuk

A general approach is presented for quantizing a metric nonlinear system on a manifold of constant curvature. It makes use of a curvature dependent procedure which relies on determining Noether symmetries from the metric. The curvature of…

数学物理 · 物理学 2015-06-19 Paul Bracken

Our aim is to establish whether geometric observables, such as length, area or volume of a physical object, viewed by different observers Poisson commute or not. To illustrate this, we compute the Poisson bracket of two lengths associated…

广义相对论与量子宇宙学 · 物理学 2026-03-09 Mehdi Assanioussi , Jerzy Kowalski-Glikman , Ilkka Mäkinen , Ludovic Varrin

We study constant mean curvature surfaces in the three-dimensional Heisenberg group. We prove that a constant mean curvature surface in a neighborhood of non-umbilic point is described by some solution of a sinh-Gordon equation subject to a…

微分几何 · 数学 2025-01-16 Dmitry Berdinsky

We consider three- and four-dimensional pseudo-Riemannian generalized symmetric spaces, whose invariant metrics were explicitly described in [15]. While four-dimensional pseudo-Riemannian generalized symmetric spaces of types A, C and D are…

微分几何 · 数学 2017-01-04 Giovanni Calvaruso , Eugenia Rosado

Constants of motion are calculated for 2+1 dimensional gravity with topology R \times T^2 and negative cosmological constant. Certain linear combinations of them satisfy the anti - de Sitter algebra so(2,2) in either ADM or holonomy…

广义相对论与量子宇宙学 · 物理学 2007-05-23 V. Moncrief , J. E. Nelson

This is a survey on the global theory of constant mean curvature surfaces in Riemannian homogeneous 3-manifolds. These ambient 3-manifolds include the eight canonical Thurston 3-dimensional geometries, i.e. R3, H3, S3, H2 \times R, S2…

微分几何 · 数学 2010-04-28 Isabel Fernandez , Pablo Mira

Recht and R\'{e} introduced the noncommutative arithmetic geometric mean inequality (NC-AGM) for matrices with a constant depending on the degree $d$ and the dimension $m$. In this paper we prove AGM inequalities with a dimension-free…

算子代数 · 数学 2017-03-03 Wafaa Albar , Marius Junge , Mingyu Zhao

We study the geometrical influence on the Brownian motion over curved manifolds. We focus on the following intriguing question: what observables are appropriated to measure Brownian motion in curved manifolds? In particular, for those…

统计力学 · 物理学 2012-12-20 Pavel Castro-Villarreal