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相关论文: On the Theory of Lorentz Surfaces with Parallel No…

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We study minimal Lorentz surfaces in the pseudo-Euclidean 4-space with neutral metric whose first normal space is two-dimensional and whose Gauss curvature $K$ and normal curvature $\varkappa$ satisfy the inequality $K^2-\varkappa^2 >0$.…

微分几何 · 数学 2019-08-28 Yana Aleksieva , Velichka Milousheva

We study surfaces with parallel normalized mean curvature vector field in Euclidean or Minkowski 4-space. On any such surface we introduce special isothermal parameters (canonical parameters) and describe these surfaces in terms of three…

微分几何 · 数学 2018-10-03 Georgi Ganchev , Velichka Milousheva

We prove that any strongly regular Weingarten surface in Euclidean space carries locally geometric principal parameters. The basic theorem states that any strongly regular Weingarten surface is determined up to a motion by its structural…

微分几何 · 数学 2011-05-17 Georgi Ganchev , Vesselka Mihova

In the present paper, we study timelike surfaces with parallel normalized mean curvature vector field in the four-dimensional Minkowski space. We introduce special isotropic parameters on each such surface, which we call canonical…

微分几何 · 数学 2024-01-18 Victoria Bencheva , Velichka Milousheva

We construct a special class of Lorentz surfaces in the pseudo-Euclidean 4-space with neutral metric which are one-parameter systems of meridians of rotational hypersurfaces with timelike or spacelike axis and call them meridian surfaces.…

微分几何 · 数学 2017-04-27 Betul Bulca , Velichka Milousheva

In the tangent plane at any point of a surface in the four-dimensional Euclidean space we consider an invariant linear map of Weingarten-type and find a geometrically determined moving frame field. Writing derivative formulas of Frenet-type…

微分几何 · 数学 2011-05-18 Georgi Ganchev , Velichka Milousheva

We consider spacelike surfaces in the four-dimensional Minkowski space and introduce geometrically an invariant linear map of Weingarten-type in the tangent plane at any point of the surface under consideration. This allows us to introduce…

微分几何 · 数学 2012-05-30 Georgi Ganchev , Velichka Milousheva

On any space-like W-surface in the three-dimensional Minkowski space we introduce locally natural principal parameters and prove that such a surface is determined uniquely up to motion by a special invariant function, which satisfies a…

微分几何 · 数学 2014-11-14 Georgi Ganchev , Vesselka Mihova

We prove that the Gauss curvature and the curvature of the normal connection of any minimal surface in the four dimensional Euclidean space satisfy an inequality, which generates two classes of minimal surfaces: minimal surfaces of general…

微分几何 · 数学 2008-06-23 Georgi Ganchev , Velichka Milousheva

We define general rotational surfaces of elliptic and hyperbolic type in the pseudo-Euclidean 4-space with neutral metric which are analogous to the general rotational surfaces of C. Moore in the Euclidean 4-space. We study Lorentz general…

微分几何 · 数学 2018-10-02 Yana Aleksieva , Velichka Milousheva , Nurettin Cenk Turgay

Weingarten surfaces are those whose principal curvatures satisfy a functional relation, whose set of solutions is called the curvature diagram or the W-diagram of the surface. Making use of the notion of geometric linear momentum of a plane…

微分几何 · 数学 2022-01-03 Paula Carretero , Ildefonso Castro

We construct a special class of Lorentz surfaces in the pseudo-Euclidean 4-space with neutral metric which are one-parameter systems of meridians of rotational hypersurfaces with lightlike axis and call them meridian surfaces. We give the…

微分几何 · 数学 2018-10-02 Velichka Milousheva

In the present paper we consider a special class of Lorentz surfaces in the four-dimensional pseudo-Euclidean space with neutral metric which are one-parameter systems of meridians of rotational hypersurfaces with timelike or spacelike axis…

微分几何 · 数学 2017-04-27 Betul Bulca , Velichka Milousheva

We review part of the classical theory of curves and surfaces in $3$-dimensional Lorentz-Minkowski space. We focus in spacelike surfaces with constant mean curvature pointing the differences and similarities with the Euclidean space.

微分几何 · 数学 2016-02-01 Rafael López

A Lorentz surface in the four-dimensional pseudo-Euclidean space with neutral metric is called quasi-minimal if its mean curvature vector is lightlike at each point. In the present paper we obtain the complete classification of…

微分几何 · 数学 2016-07-15 Velichka Milousheva , Nurettin Cenk Turgay

A marginally trapped surface in the four-dimensional Minkowski space is a spacelike surface whose mean curvature vector is lightlike at each point. We associate a geometrically determined moving frame field to such a surface and using the…

微分几何 · 数学 2012-05-30 Georgi Ganchev , Velichka Milousheva

For a two-dimensional surface in the four-dimensional Euclidean space we introduce an invariant linear map of Weingarten type in the tangent space of the surface, which generates two invariants k and kappa. The condition k = kappa = 0…

微分几何 · 数学 2008-04-29 Georgi Ganchev , Velichka Milousheva

The fact that minimal surfaces in the four-dimensional Euclidean space admit natural parameters implies that any minimal surface is determined uniquely up to a motion by two curvature functions, satisfying a system of two PDE's (the system…

微分几何 · 数学 2016-09-06 Georgi Ganchev , Krasimir Kanchev

A local classification of spacelike surfaces in Minkowski 4-space, which are invariant under spacelike rotations, and with mean curvature vector either vanishing or lightlike, is obtained. Furthermore, the existence of such surfaces with…

广义相对论与量子宇宙学 · 物理学 2009-08-05 Stefan Haesen , Miguel Ortega

Spacelike intrinsic rotational surfaces with constant mean curvature in the Lorentz-Minkowski space $\E_1^3$ have been recently investigated by Brander et al., extending the known Smyth's surfaces in Euclidean space. Assuming that the…

微分几何 · 数学 2024-12-02 Seher Kaya , Rafael López
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