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arXiv research

A locally-built, LLM-digested index of recent arXiv papers in quant finance, geometry/topology, and statistical ML — keyword search served straight from SQLite on this machine.

168,657 papers · 148 categories

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295988117 · Jun 202019922001200920172026
48 results for Einstein's static universe

Explicit models for the restricted conformal group of the Einstein static universe of dimension greater than two and for its universal covering group are constructed. Based on these models, as an application we determine all oriented and time-oriented conformal Lorentz manifolds whose restricted conformal group has max…

2019-09-18abs ↗pdf ↗

It is shown that any two-dimensional spacetimes with compact Cauchy surfaces can be causally isomorphically imbedded into the two-dimensional Einstein's static universe. Also, it is shown that any two-dimensional globally hyperbolic spacetimes are conformally equivalent to a subset of the two-dimensional Einstein's sta…

2015-01-15abs ↗pdf ↗

Study classifies and characterizes translators in hyperbolic static universe.

problem Classifying and characterizing translators in hyperbolic static universe.
method Classified and characterized translators foliated by horospheres and rotationally invariant ones, both space-like and time-like.
result Obtained a characterization of the bowl and certain translators foliated by horospheres.

Classifies conformal transformations in spacetimes without observer horizons.

problem Understanding conformal transformations in spacetimes without observer horizons.
method Proves classification of conformal transformations into two types: escaping and non-escaping.
result Conformal transformations of Einstein's static universe are classified.

We prove that any 4-dimensional geodesically complete spacetime with a timelike Killing field satisfying the vacuum Einstein field equation Ric(gM)=λgMRic(g_{M})=λg_{M} with nonnegative cosmological constant λ0λ\geq 0 is flat. When dim 5\geq 5, if the spacetime is assumed to be static additionally, we prove that its universal …

2016-06-02abs ↗pdf ↗

The paper finds exact solutions to a complex Einstein-Dirac-Maxwell system on 4D Sasakian spacetimes.

problem Finding exact solutions to an Einstein-Dirac-Maxwell system with Sasakian quasi-Killing spinors.
method Constructing a family of exact solutions on four-dimensional static Sasakian spacetimes using the Sasakian frame.
result Closed and open universe models are found with specific energy conditions.

The group of conformal diffeomorphisms and the group of causal automorphisms on two-dimensional globally hyperbolic spacetimes are clarified. It is shown that if spacetimes have non-compact Cauchy surfaces, then the groups are subgroups of that of two-dimensional Minkowski spacetime, and if spacetimes have compact Cauc…

2015-01-28abs ↗pdf ↗

In this paper, we present two observations about static spherically symmetric solutions of the Einstein-Klein-Gordon equations. The first is a comment extending the well-known result of the existence of static states (i.e. standing wave solutions) of the Einstein-Klein-Gordon equations. The second more important observ…

2012-12-27abs ↗pdf ↗

Trajectories of light rays in a static spacetime are described by unparametrised geodesics of the Riemannian optical metric associated with the Lorentzian spacetime metric. We investigate the uniqueness of this structure and demonstrate that two different observers, moving relative to one another, who both see the univ…

2011-01-23abs ↗pdf ↗

We compute a Bochner type formula for static three-manifolds and deduce some applications in the case of positive scalar curvature. We also explain in details the known general construction of the (Riemannian) Einstein (n+1)-manifold associated to a maximal domain of a static n-manifold where the static potential is po…

2015-03-12abs ↗pdf ↗

The goal of this article is to study compact quasi-Einstein manifolds with boundary. We provide boundary estimates for compact quasi-Einstein manifolds simi\-lar to previous results obtained for static and VV-static spaces. In addition, we show that compact quasi-Einstein manifolds with connected boundary and satisfyi…

2019-11-22abs ↗pdf ↗

Study finds conditions for certain warped product manifolds to be quasi-Einstein.

problem Conditions for quasi-Einstein sequential warped product manifolds.
method Investigated necessary and sufficient conditions for specific types of manifolds.
result Identified conditions for sequential warped product manifolds to be quasi-Einstein.

Study geometric inequalities and boundary estimates for Einstein-type manifolds with boundary.

problem Investigate geometric properties of Einstein-type manifolds with boundary.
method Investigate geometric inequalities and establish boundary estimates.
result Established boundary estimates in terms of eigenvalues and Brown-York mass.

In this paper we consider an Einstein-type equation which generalizes important geometric equations, like static and critical point equations. We prove that a complete Einstein-type manifold with fourth-order divergence-free Weyl tensor and zero radial Weyl curvature is locally a warped product with (n1)(n-1)-dimensional…

2019-04-28abs ↗pdf ↗

The study finds static solutions in symplectic curvature flow in 4D.

problem Finding static solutions in symplectic curvature flow in 4D.
method Derived a local normal form for static solutions and used Cartan-Kahler theorem for solitons.
result Every complete static solution to symplectic curvature flow in 4D is Kahler-Einstein.

The paper explores stable surfaces in Einstein-Maxwell theory, proving mass bounds and nonexistence results.

problem Exploring stable surfaces in static Einstein-Maxwell space-time.
method Using mean-stable surfaces theory to prove properties of lapse functions and mass bounds.
result Proves ADM mass is bounded by Hawking quasi-local mass.

Essentially, some conditions for the Riemannian factor and the warping function of a standard static space-time are obtained in order to guarantee that no nontrivial warping function on the Riemannian factor can make the standard static space-time Einstein.

2004-06-03abs ↗pdf ↗

The paper explores rigidity and splitting theorems for sub-static spaces with minimal hypersurfaces.

problem Rigidity and splitting problems for sub-static systems with boundary.
method Local and global splitting theorems, boundary integral inequalities, Liouville theorem.
result Improvements in rigidity and splitting results for sub-static spaces, including vacuum and non-vacuum cases.

A complete characterization is obtained of the asymptotic behavior of solutions of the static vacuum Einstein equations which have a (pseudo)-compact horizon or boundary and are complete away from the boundary. It is proved that the time-symmetric space-like hypersurface has only finitely many ends, each of which is ei…

2000-01-07abs ↗pdf ↗

New findings on static near horizon geometries and quasi-Einstein manifolds, including rigidity results for negative cosmological constant.

problem Rigidity of quasi-Einstein manifolds under different cosmological constant conditions.
method Analysis of quasi-Einstein equations on closed manifolds, focusing on static vacuum solutions and their properties.
result For negative cosmological constant, rigidity holds under specific conditions on the 1-form \(X\), including incompressibility, constant norm, and nontrivial cohomology.

The paper extends gluing theorems for linearized gravitational fields in static spacetimes with cosmological constant.

problem Establishing gluing theorems for linearized vacuum gravitational fields on characteristic surfaces.
method Analyzing linearised Einstein equations in Bondi gauge on static four-dimensional spacetimes with cosmological constant.
result Generalization and extension of gluing theorems to include cosmological constant and arbitrary topology.

In this paper we utilize symmetries in order to exhibit exact solutions to Einstein's equation of a perfect fluid on a static manifold all of whose spatial factor belongs to the conformal class of a Riemannian space of constant curvature.

2019-04-30abs ↗pdf ↗

The paper investigates geometrical aspects of static spacetime with almost gradient Ricci solitons.

problem Geometrical properties of static spacetime with almost gradient Ricci solitons.
method Analyzing conditions and properties of static spacetime with almost gradient Ricci solitons.
result Conditions and properties of static spacetime with almost gradient Ricci solitons are determined.

The Einstein universe is the conformal compactification of Minkowski space. It also arises as the ideal boundary of anti-de Sitter space. The purpose of this article is to develop the synthetic geometry of the Einstein universe in terms of its homogeneous submanifolds and causal structure, with particular emphasis on d…

2007-06-20abs ↗pdf ↗

We prove that given any smooth metric γγ and smooth positive function HH on S2S^{2}, there is a constant λ>0λ> 0, depending on (γ,H)(γ, H), and an asymptotically flat solution (M,g,u)(M, g, u) of the static vacuum Einstein equations on M=R3B3M = {\mathbb R}^{3} \setminus B^{3}, such that the induced metric and mean curvature of $…

2015-07-21abs ↗pdf ↗

We will discuss fundamental domains for actions of discrete groups on the 3-dimensional Einstein Universe. These will be bounded by crooked surfaces, which are conformal compactifications of surfaces that arise in the construction of Margulis spacetimes. We will show that there exist pairwise disjoint crooked surfaces …

2013-07-24abs ↗pdf ↗

The Yamabe invariant is linked to static potentials and eigenvalues.

problem The relationship between Yamabe invariant and static potentials/eigenvalues.
method Analyzes the Yamabe invariant in the context of static potentials and eigenvalues of the Laplacian.
result The Yamabe invariant is closely tied to static potentials and the first eigenvalue of the Laplacian.

In hyperbolic space, the angle of intersection and distance classify pairs of totally geodesic hyperplanes. A similar algebraic invariant classifies pairs of hyperplanes in the Einstein universe. In dimension 3, symplectic splittings of a 4-dimensional real symplectic vector space model Einstein hyperplanes and the inv…

2017-02-27abs ↗pdf ↗

Unique domain found in Einstein universe, simplifying manifold classification.

problem Classifying closed conformally flat manifolds with proper development.
method Identifying and analyzing almost-homogeneous domains in the Einstein universe.
result Found a unique domain (diamond) in the Einstein universe that simplifies manifold classification.