Results 61 to 70 of about 74,207 (261)
Some submersions of CR-hypersurfaces of Kaehler-Einstein manifold
International Journal of Mathematics and Mathematical Sciences, 2003 The Riemannian submersions of a CR-hypersurface M of a Kaehler-Einstein manifold M˜ are studied. If M is an extrinsic CR-hypersurface of M˜, then it is shown that the base space of the submersion is also a Kaehler-Einstein manifold.
Vittorio Mangione
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Ambient connections realising conformal Tractor holonomy
, 2006 For a conformal manifold we introduce the notion of an ambient connection, an affine connection on an ambient manifold of the conformal manifold, possibly with torsion, and with conditions relating it to the conformal structure.
A Čap +10 more
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On Four Dimensional Einstein Manifolds [PDF]
Communications, Faculty Of Science, University of Ankara Series A1Mathematics and Statistics, 1987 The paper contains an argument leading to a classification of Einstein four-manifolds with a 3-dimensional Abelian group of isometries, first established by Kasner in 1923.
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Isotropic quasi-Einstein manifolds [PDF]
Classical and Quantum Gravity, 2019 We investigate the local structure of four-dimensional Lorentzian quasi-Einstein manifolds under conditions on the Weyl tensor. We show that if the Weyl tensor is harmonic and the potential function preserves this harmonicity then, in the isotropic case, the manifold is necessarily a $pp$-wave. Using the quasi-Einstein equation, further conclusions are
M Brozos-Vázquez +2 more
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Flat Optics for Polarization Structure Engineering from 2D to 3D
Advanced Optical Materials, EarlyView.Metasurfaces have transformed polarization control by enabling precise engineering of complex polarization structures. This review explores their evolution from generating 2D polarization structures to shaping fully 3D polarization fields. By unlocking the unprecedented control over the polarization and spectral information of light, these advances ...
Buxiong Qi, Yan Li, Xianzhong Chen
wiley +1 more source
ON-RECURRENT LORENTZIAN -KENMOTSU MANIFOLDS
Süleyman Demirel Üniversitesi Fen-Edebiyat Fakültesi Fen Dergisi, 2009 : In this paper, we study Lorentzian -Kenmotsu manifold and we shown that -recurrent Lorentzian -Kenmotsu manifold is an Einstein manifold and a pseudo-projective -recurrent Lorentzian -Kenmotsu manifold is an - Einstein manifold.
G.T. SREENIVASA +3 more
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Cloaking and Antennas: From Theoretical Paradigms to Next‐Generation Intelligent Systems
Advanced Optical Materials, EarlyView.The inception of electromagnetic cloaking sparked an immediate question: Can antennas be made invisible? Two decades later, this review charts the intertwined progress of major cloaking strategies (from transformation optics to scattering cancellation), metasurface technology, and their application to antennas, revealing how AI‐enabled devices are ...
Helen Guo, Xun Li
wiley +1 more source
Toward a Universal Czochralski Growth Model Leveraging Data‐Driven Techniques
Advanced Theory and Simulations, EarlyView.This data‐driven study investigates Czochralski growth using Decision Trees, Symbolic Regression, ANN, and SHAP to assess the impact of 21 process and design parameters on crystal quality. Trained on 632 CFD simulation datasets across four crystalline materials, it demonstrates the feasibility of a universal Cz model applicable to various ...
Natasha Dropka +4 more
wiley +1 more source
Remarks on the Myers-Perry and Einstein Gauss-Bonnet Rotating Solutions
, 2010 The Kerr-type solutions of the five-dimensional Einstein and Einstein-Gauss-Bonnet equations look pretty similar when written in Kerr-Schild form. However the Myers-Perry spacetime is circular whereas the rotating solution of the Einstein-Gauss-Bonnet ...
ANDRES ANABALÓN +5 more
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Quaternionic contact Einstein manifolds [PDF]
Mathematical Research Letters, 2016 The main result is that the qc-scalar curvature of a seven dimensional quaternionic contact Einstein manifold is a constant. In addition, we characterize qc-Einstein structures with certain flat vertical connection and develop their local structure equations. Finally, regular qc-Ricci flat structures are shown to fibre over hyper-Kahler manifolds.
Ivan Minchev +2 more
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