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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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591418 · Jun 202619922001200920172026
48 results for pseudosymmetric spacetimes

The paper finds conditions for pseudosymmetric spacetimes to be perfect fluids.

problem Characterizing pseudosymmetric spacetimes as perfect fluids.
method Analyzes generalized Robertson-Walker spacetimes, conformally flat spacetimes, and dust fluids.
result Conditions for pseudosymmetric spacetimes to be perfect fluids are established.

Investigates geometric properties of Bardeen black hole spacetime.

problem Examines curvature properties of Bardeen black hole spacetime.
method Analyzes pseudosymmetry, pseudosymmetric Weyl curvature, and recurrent structures.
result Bardeen spacetime is a manifold of pseudosymmetry Weyl curvature and satisfies special recurrent like structure.

This paper aims to investigate the curvature restricted geometric properties admitted by Melvin magnetic spacetime metric, a warped product metric with 11-dimensional fibre. For this, we have considered a Melvin type static, cylindrically symmetric spacetime metric in Weyl form and it is found that such metric, in gen…

2019-08-20abs ↗pdf ↗

The charged Nariai spacetimes are the exact solutions of Einstein-Maxwell field equations with positive cosmological constant and such a spacetime is the direct topological product of a 22-dimentional de-Sitter spacetime with a round 22-sphere of constant radius. The present paper deals with the investigation of curv…

2019-02-08abs ↗pdf ↗

The paper investigates various generalizations of semisymmetric and pseudosymmetric manifolds.

problem Exploring different curvature tensor generalizations of semisymmetric and pseudosymmetric manifolds.
method Systematic review and examination of geometric structures with physical examples.
result Proper existence of various geometric structures, including Ricci pseudosymmetric manifolds.

The main objective of the present paper is to investigate the curvature properties of generalized pp-wave metric. It is shown that generalized pp-wave spacetime is Ricci generalized pseudosymmetric, 2-quasi-Einstein and generalized quasi-Einstein in the sense of Chaki. As a special case it is shown that pp-wave spaceti…

2017-02-24abs ↗pdf ↗

The paper examines geometric properties of a specific black hole spacetime.

problem Curvature properties of a Hayward black hole spacetime.
method Analyzes the curvature properties of Hayward black hole spacetime using Einstein field equations.
result The Hayward black hole spacetime is an Einstein manifold and exhibits various types of pseudosymmetry.

The object of the present paper is to study some types of Ricci pseudosymmetric (LCS)n(LCS)_n-manifolds whose metric is Ricci soliton. We found the conditions when Ricci soliton on concircular Ricci pseudosymmetric, projective Ricci pseudosymmetric, W3W_{3}-Ricci pseudosymmetric, conharmonic Ricci pseudosymmetric, conforma…

2017-07-12abs ↗pdf ↗

Definition of (Ta,Tb)({\cal T}_{a},{\cal T}_{b})-pseudosymmetric semi-Riemannian manifold is given. (Ta,Tb)({\cal T}_{a},{\cal T}_{b})-pseudosy mmetric (N(k),ξ)(N(k),ξ)-semi-Riemannian manifolds are classified. Some results for Ta{\cal T}_{a}-pseudosymmetric (N(k),ξ)(N(k),ξ)-semi-Riemannian manifolds are obtained. $({\cal T}_{a},{\cal T}_{b…

2012-02-29abs ↗pdf ↗

Study explores geometric properties of Vaidya-Bonner-de Sitter spacetime.

problem Exploring geometric properties of Vaidya-Bonner-de Sitter spacetime.
method Analyzing conformal curvature, conharmonic curvature, and other curvatures.
result VBdS spacetime exhibits various pseudosymmetric structures and geometric features.

In the literature, there are two different notions of pseudosymmetric manifolds, one by Chaki [7] and other by Deszcz [16], and there are many papers related to these notions. The object of the present paper is to deduce necessary and sufficient conditions for a Chaki pseudosymmetric [7] (resp. pseudo Ricci symmetric […

2014-05-09abs ↗pdf ↗

The curvature properties of Robinson-Trautman metric have been investigated. It is shown that Robinson-Trautman metric admits several kinds of pseudosymmetric type structures such as Weyl pseudosymmetric, Ricci pseudosymmetric, pseudosymmetric Weyl conformal curvature tensor etc. Also it is shown that the difference $R…

2017-01-22abs ↗pdf ↗

Study geometric properties and physical applications of mixed quasi-Einstein spacetime.

problem Characterize geometric and physical properties of mixed quasi-Einstein spacetime.
method Analyze geometric conditions and curvature tensors on mixed quasi-Einstein and nearly quasi-Einstein manifolds.
result Establish conditions for specific curvature tensors and spacetime structures.

For compact Kählerian manifolds, the holomorphic pseudosymmetry reduces to the local symmetry if additionally the scalar curvature is constant and the structure function is non-negative. Similarly, the holomorphic Ricci-pseudosymmetry reduces to the Ricci-symmetry under these additional assumptions. We construct exampl…

2009-03-29abs ↗pdf ↗

The study characterizes symmetries in Kaehler manifolds.

problem Understanding symmetries in Kaehler manifolds.
method Analyzing specific types of Kaehler manifolds: constant holomorphic sectional curvature, semisymmetric, and holomorphically pseudosymmetric.
result Characterization results and geometric interpretation of the complex Tachibana tensor.

We determine a particular class of Roter type warped product manifolds. We show that every manifold of that class admits a geodesic mapping onto a some Roter type warped product manifold. Moreover, both geodesically related manifolds are pseudosymmetric of constant type.

2018-12-03abs ↗pdf ↗

The object of this paper is study (ε)(ε)-para-Sasakian 3-manifolds satisfying certain conditions on the Z\mathcal{Z} tensor. We characterize, Z\mathcal{Z}-symmetric; Z\mathcal{Z}-semisymmetric; Z\mathcal{Z}-pseudosymmetric; and projectively Z\mathcal{Z}-semisymmetric conditions on an (ε)(ε)-para-Sasakian 3-manifold.

2019-09-12abs ↗pdf ↗

The paper explores symmetries in Kähler manifolds using Ricci tensor properties.

problem Investigating symmetries in Kähler manifolds involving Ricci tensor.
method Analyzing properties of Kähler-Einstein spaces and their generalizations.
result Clarified the geometric role of holomorphic Ricci pseudosymmetry and established new criteria for Kähler manifolds to be Einstein.

In this paper, N(κ)N(κ)-contact metric manifolds satisfying the conditions C~(ξ,X)C~=0\widetilde{C}(ξ,X)\cdot\widetilde{C}=0, C~(ξ,X)R=0\widetilde{C}(ξ,X)\cdot R=0, C~(ξ,X)S=0\widetilde{C}(ξ,X)\cdot S=0, C~(ξ,X)C=0\widetilde{C}(ξ,X)\cdot C=0, CS=0C\cdot S=0 and RC=fCQ(g,C)R\cdot C=f_{C}Q(g,C) have been investigated and obtained their classification. Among others i…

2019-06-11abs ↗pdf ↗

In this paper we study the 3-dimensional (ε)(\varepsilon) -para Sasakian manifolds. We obtain an necessary and sufficient condition for an (ε)(\varepsilon ) -para Sasakian 3 -manifold to be an indefinite space form. We show that a Ricci-semi-symmetric (ε)(\varepsilon) -para Sasakian 3 -manifold is an indefinite space form…

2009-11-25abs ↗pdf ↗

We consider (flat) Cauchy-complete GH spacetimes, i.e., globally hyperbolic flat lorentzian manifolds admitting some Cauchy hypersurface on which the ambient lorentzian metric restricts as a complete riemannian metric. We define a family of such spacetimes - model spacetimes - including four subfamilies: translation sp…

2004-02-16abs ↗pdf ↗

The paper introduces and analyzes pseudo generalized Ricci-recurrent spacetimes in modified gravity.

problem Characterizing and analyzing pseudo generalized Ricci-recurrent spacetimes in modified gravity.
method Introducing and characterizing pseudo generalized Ricci-recurrent spacetimes, proving their properties, and studying their impact under modified gravity scenarios.
result Pseudo generalized Ricci-recurrent spacetimes represent specific spacetime types under modified gravity scenarios.

The study characterizes spacetimes with quasi-constant sectional curvature and explores their properties in F(R)\mathcal{F}(\mathcal{R})-gravity.

problem Characterizing spacetimes with quasi-constant sectional curvature.
method Investigation through examples, proofs, and analysis of energy conditions.
result A spacetime of quasi-constant sectional curvature can represent a Robertson Walker spacetime or a static spacetime.

The article introduces pseudo generalized Ricci-recurrent spacetimes and their applications in modified gravity.

problem Characterizing and understanding pseudo generalized Ricci-recurrent spacetimes.
method Introduced and characterized pseudo generalized Ricci-recurrent spacetimes, provided examples, and studied their implications in modified gravity.
result Pseudo generalized Ricci-recurrent spacetimes represent perfect fluid spacetimes and can model dark energy epochs or static spacetimes.

The paper studies the past inextendibility of FLRW spacetimes using the VDR asymptote.

problem Investigating the past inextendibility of FLRW spacetimes.
method Using the volume-distance-ratio (VDR) asymptote to assess spacetime inextendibility criteria.
result Conditions for past inextendibility of FLRW spacetimes are identified.

The study characterizes GRW spacetimes with gradient solitons and phantom era.

problem Characterizing generalized Robertson-Walker spacetimes with gradient solitons.
method Examined gradient type Ricci solitons and (m,τ)(m,τ)-quasi Einstein solitons in GRW spacetimes.
result Demonstrated that GRW spacetimes can be Robertson-Walker or phantom era spacetimes under certain conditions.

Characterizes Lorentzian manifolds embeddable in Minkowski spacetime.

problem Identifying Lorentzian manifolds embeddable in Minkowski spacetime.
method Characterization and proof of embeddability conditions.
result Lorentzian manifolds embeddable in Minkowski spacetime coincide with globally hyperbolic spacetimes.

New proof shows FLRW spacetimes can't be extended smoothly in certain axisymmetric cases.

problem Proving smooth extension of FLRW spacetimes in specific spacetime classes.
method Extending previous work on spherically symmetric spacetimes to axisymmetric spacetimes.
result Demonstrates C0C^0-inextendibility for FLRW spacetimes in a subclass of axisymmetric spacetimes.

Characterizes pseudo B-symmetric spacetimes and their implications in f(R) gravity.

problem Characterizing pseudo B-symmetric spacetimes and their properties.
method Analyzes Codazzi type of B-tensor and applies f(R) gravity model.
result Pseudo B-symmetric spacetimes with Codazzi type B-tensor are conformally flat and Robertson-Walker spacetimes.

Study maximal hypersurfaces in open spacetimes using a maximum principle.

problem Characterize maximal hypersurfaces in open spacetimes.
method Use a generalized maximum principle to analyze hypersurfaces in spatially open Generalized Robertson-Walker spacetimes.
result Provide new uniqueness and non-existence results for complete maximal hypersurfaces in open Robertson-Walker spacetimes.

The study explores properties of a specific type of spacetime.

problem Discussing geometric and physical properties of hyper-generalised quasi-Einstein spacetime.
method Analyzing various types of pseudosymmetry and Ricci symmetry over the spacetime.
result Proved the existence of a non-trivial hyper-generalised quasi-Einstein spacetime.

New findings show cosmological constant as initial condition for non-isotropic spacetimes.

problem Cosmological constant as initial condition in non-isotropic spacetimes.
method Generalized previous results to non-isotropic spacetimes.
result Quasi de Sitter expansion for early universe, potential for inflationary scenarios.

Study finds unique and non-existent constant mean curvature hypersurfaces in specific spacetimes.

problem Finding unique and non-existent constant mean curvature spacelike hypersurfaces.
method Geometric and physical assumptions applied to Generalized Robertson-Walker spacetimes.
result New uniqueness and non-existence results for complete spacelike hypersurfaces.

Study revisits Bondi mass and discusses memory effect in polyhomogeneous spacetimes.

problem Analyzing the asymptotic behavior and memory effect in polyhomogeneous spacetimes.
method Revisits Bondi mass using Iyer-Wald formalism and discusses memory effect in vacuum polyhomogeneous spacetimes.
result The balance law remains unchanged in polyhomogeneous spacetimes with logarithmic terms.

In 2+1 dimensions, all complete spacetimes are cylindrical.

problem Understanding rigidity of Ricci flow spacetimes in (2+1)(2+1) dimensions.
method Analyzing complete and sufficiently regular spacetimes, showing they must be cylindrical.
result Every spatial slice is diffeomorphic to a fixed surface, and the spacetime is isometric to a classical Ricci flow.

The study examines perfect fluid spacetimes and their properties.

problem Characterizing properties of perfect fluid spacetimes with concircular vector fields.
method Analyzing the conformal curvature tensor, state equation, and solitons in perfect fluid spacetimes.
result Perfect fluid spacetimes with concircular vector fields have specific properties related to the state equation and solitons.