In this study, we study rotational hypersurfaces in 4-dimensional Lorentz-Minkowski space. We find the about spacelike axis according to Gaussian and mean curvatures $E_{1}^{4}$ give some results with aid of curvatures. After that, deal Gauss map hypersurface by obtaining obtain second third Laplace-Beltrami operators on $E_{1}^{4}$. Also, these characterizations for timelike lightlike axes, too.

In this paper, we give a geometric condition for a CR map, which sends a CR non-umbilical Levi non-degenerate hypersurface in Cn+1 into the hyperquadric in Cn+2 with the same signature, to be CR transversal.

In this article we obtain the pinching of the null sectional curvature of CRlightlike submanifolds of an inde…nite Hermitian manifold. As a result of this inequality we conclude some non-existence results of such lightlike submanifolds.Moreover using the Index form we prove more non-existence results for CR-lightlike submanifolds. 1. Introduction The theory of submanifolds of a Riemannian or se...

We study the inviscid limit problem of the incompressible flows in the presence of both impermeable regular boundaries and a hypersurface transversal to the boundary across which the inviscid flow has a discontinuity jump. In the former case, boundary layers have been introduced by Prandtl as correctors near the boundary between the inviscid and viscous flows. In the latter case, the viscosity ...

By establishing some differential geometry theory on the 1-lightlike surfaces, we show several geometric properties of the 1-lightlike surfaces which are completely different from non-lightlike surfaces. Based on these theories, we consider the singularities of the 1-lightlike surfaces in semiEuclidean 4-space with index two as an application of the theory of Legendrian singularities. We charac...

In this paper, we study curves in the lightlike cone. We first obtain the conformally invariant arc length in the (n+1)-dimensional lightlike cone and then characterize some curves in the 2-dimensional lightlike cone and 3-dimensional lightlike cone. MSC 2000: 53A04, 53A30, 53B30