Yazar "Erdogan, Mehmet" seçeneğine göre listele
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Öğe A characterization of H- strictly convex hypersurfaces in de Sitter space S16(Academic Journals, 2009) Erdogan, Mehmet; Yilmaz, GuelsenIn this study, we introduce a H-strictly convex hypersurface in the 6-dimensional unitary de Sitter space S-1(6) and give a lower bound approximation for the Ricci curvature of such hypersurfaces under some appropriate conditions.Öğe A characterization of H-strictly convex hypersurfaces in hyperbolic space by the Ricci curvatures(Geometry Balkan Press, 2010) Erdogan, Mehmet; Alo, JetaIn previous papers the first author obtained some upper bound estimations for the Ricci curvatures of the hypersurfaces in a sphere ([6]) and in a hyperbolic manifold ([4], [5]) by the extremum principle. In the present paper, we introduce an H-strictly convex hypersurface in the hyperbolic space N(n+1) and using a result given by B.Y.Chen in [2] we give a lower bound approximation for the Ricci curvature of a H-strictly convex hypersurface in N(n+1).Öğe A characterization of H-strictly convex hypersurfaces in hyperbolic space by the Ricci curvatures(Geometry Balkan Press, 2010) Erdogan, Mehmet; Alo, JetaIn previous papers the first author obtained some upper bound estimations for the Ricci curvatures of the hypersurfaces in a sphere ([6]) and in a hyperbolic manifold ([4], [5]) by the extremum principle. In the present paper, we introduce an H-strictly convex hypersurface in the hyperbolic space N(n+1) and using a result given by B.Y.Chen in [2] we give a lower bound approximation for the Ricci curvature of a H-strictly convex hypersurface in N(n+1).Öğe Complete spacelike hypersurfaces with constant scalar curvature and sectional curvatures ? 1 in De Sitter space S16(1)(Academic Journals, 2010) Erdogan, Mehmet; Alo, JetaHypersurfaces with constant scalar curvature and two different principal curvatures isometrically immersed in an (n+1)-dimensional space form M-,M-+1 (C) of constant curvature c and especially in Sn+1(c) have been extensively investigated within the last four decades. In the present work, we study complete spacelike hypersurfaces with constant scalar curvature and have sectional curvatures K(pi) >= 1 in de Sitter space S-1(6)(1) and find a result on the type number of such a hypersurface.Öğe The Equations of Motion of a Null Curve in Lightlike Cone of 3-Dimensonal Minkowski Space(Beykent Üniversitesi, 2009) Erdogan, Mehmet; Alo, Jeta; Yilmaz, GulsenIn this article we investigate null curves in the lightlike cone of 3-dimensional Lorentz Minkowski space and give some characterizations of these curves.We also obtain the equations of motion of a null curve in the lightlike cone. Mathematics Subject Classificiation : 53B30, 53B50, 53C80Öğe A LOWER BOUND ESTIMATION FOR THE RICCI CURVATURE OF A HYPERSURFACE IN A HYPERBOLIC SPACE(Akademiai Kiado Rt, 2009) Erdogan, MehmetIn some previous papers the author gave an upper bound estimation for the Ricci curvature of a hypersurface in a hyperbolic space and in a sphere, see [4] and [5]. In the present paper, we give a lower bound estimation for the Ricci curvature of a compact connected embedded hypersurface in a hyperbolic space via the maximum principle given by H. Omori in [11].Öğe On ?-Conformally and ?-Pseudo Projectively Flat Lorentzian Sasakian Manifolds with Tanaka-Webster Connection(Chiang Mai Univ, Fac Science, 2022) Erdogan, Mehmet; Alo, JetaIn this work, the Tanaka-Webster connection on a Lorentzian Sasakian manifold is defined and the notions xi-quasi conformally and xi-pseudo projectively flat structures on a Lorentzian Sasakian manifold are introduced. After that, it is proved that if any Lorentzian Sasakian manifold with Tanaka-Webster connection is an eta- Einstein manifold, then the Thnaka-Webster connection (del) over cap is xi-conformally flat. Furthermore, we give some structure theorems on Lorentzian Sasakian manifold with respect to the Tanaka-Webster connection.Öğe On the type number of a hypersurface in the 6-dimensional sphere(Walter De Gruyter Gmbh, 2014) Erdogan, Mehmet; Pirincci, Beran; Alo, Jeto; Yilmaz, GulsenWe prove that if a hypersurface M with constant scalar curvature in S 6 ( 1) has the sectional curvatures <= 1, then the type number of M is not greater than 1.Öğe SOME PROPERTIES OF LORENTZIAN SASAKIAN MANIFOLDS WITH TANAKA-WEBSTER CONNECTION(Int Center Scientific Research & Studies, 2012) Erdogan, Mehmet; Alo, Jeta; Pirincci, Beran; Yilmaz, GulsenIn this work we study some curvature properties of Lorentzian Sasakian manifolds with respect to the Tanaka-Webster connection and obtain some results about the slant curves of the 3-dimensional Lorentzian Sasakian manifold with Tanaka-Webster connection.
