Lagrangian //-umbilical submanifolds are the "simplest" Lagrangian submanifolds next to totally geodesic ones in complex-space-forms. The class of Lagrangian //-umbilical submanifolds in complex Euclidean spaces includes Whitney's spheres and Lagrangian pseudo-spheres. For each submanifold M of Euclidean «-space and each unit speed curve F in the complex plane, we introduce the notion of the co...

In complex two-plane Grassmannians G2(Cm+2) = SU2+m/S(U2?Um), it is known that a real hypersurface satisfying the condition (L?(k)?R?)Y (L?R?)Y locally congruent to an open part of tube around totally geodesic G2(Cm+1) in G2(Cm+2). this paper, as abient space, we consider hyperbolic Grassmannian SU2,m/S(U2?Um) and give complete classification Hopf hypersurfaces with above condition.

It is well known that the semi-Riemannian (pseudo-Riemannian) manifolds (M,g) of Lorentzian signature play a special role in geometry and physics, and that they are models of space time of general relativity. Let Mn+1 p (c) be an (n+1)-dimensional complete connected semi-Riemannian manifold with constant sectional curvature c and index p (see [13, page 227]). It is called an indefinite space fo...

and Applied Analysis 3 in the normal bundle T⊥M, and AN is the shape operator of the second fundamental form. Moreover, we have g ANX, Y g h X,Y ,N , 2.4 where g denotes the Riemannian metric onM as well as the metric induced onM. The mean curvature vector H on M is given by

In this paper, we study half-lightlike submanifolds of a semi-Riemannian manifold such that the shape operator of screen distribution is conformal to the shape operator of screen transversal distribution. We mainly obtain some results concerning the induced Ricci curvature tensor and the null sectional curvature of screen transversal conformal half-lightlike submanifolds. 2010 Mathematics Subje...

In this paper, we study the curvature of a semi-Riemannian manifold M̃ of quasi-constant curvature admits some half lightlike submanifolds M . The main result is two characterization theorems for M̃ admits extended screen homothetic and statical half lightlike submanifolds M such that the curvature vector field of M̃ is tangent to M .

In this paper, we study half lightlike submanifolds M of an indefinite generalized Sasakian space form M̄(f1, f2, f3), with an indefinite trans-Sasakian structure of type (α, β), subject to the condition that the structure vector field of M̄ is tangent to M . Our main result is a characterization theorem for such a half lightlike submanifold. Mathematics Subject Classification: 53C25, 53C40, 53C50