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Author: Ünal, BSubject: warped products

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Now showing 1 - 3 of 3
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    Article
    Citation - WoS: 77
    Citation - Scopus: 85
    Curvature of multiply warped products
    (Elsevier, 2005) Dobarro, F; Ünal, B
    In this paper, we study Ricci-flat and Einstein-Lorentzian multiply warped products. We also consider the case of having constant scalar curvatures for this class of warped products. Finally, after we introduce a new class of space-times called as generalized Kasner space-times, we apply our results to this kind of space-times as well as other relativistic space-times, i.e., Reissner-Nordstrom, Kasner space-times, Banados-Teitelboim-Zanelli and de Sitter black hole solutions. (c) 2004 Elsevier B.V. All rights reserved.
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    Article
    Citation - WoS: 77
    Citation - Scopus: 74
    Doubly Warped Products
    (Elsevier Science Bv, 2001) Ünal, B
    In this paper we study geodesic completeness of Riemannian doubly warped products and Lorentzian doubly warped products. We give necessary conditions for generalized Robertson-Walker spacetimes with doubly warped product spacial parts to be globally hyperbolic. We also state some results about killing and conformal vector fields of doubly warped products.
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    Article
    Citation - WoS: 30
    Citation - Scopus: 32
    Geodesic Structure of Standard Static Space-Times
    (Elsevier Science Bv, 2003) Allison, DE; Ünal, B
    The geodesic structure of standard static space-times is studied and conditions are found which imply nonreturning and pseudoconvex geodesic systems. As a consequence, it is shown that if the Riemannian factor manifold F satisfies the nonreturning property and has a pseudoconvex geodesic system and if the warping function f : F --> (0, infinity) is bounded above then the standard static space-time (f)(a, b) x F is geodesically connected. (C) 2002 Elsevier Science B.V. All rights reserved.