scholarly journals Delaunay surfaces in S3(ρ)

Filomat ◽  
2019 ◽  
Vol 33 (4) ◽  
pp. 1191-1200 ◽  
Author(s):  
J. Arroyo ◽  
O.J. Garay ◽  
A. Pámpano

Recently, invariant constant mean curvature (CMC) surfaces in real space forms have been characterized locally by using extremal curves of a Blaschke type energy functional [5]. Here, we use this characterization to offer a new approach to some global results for CMC rotational surfaces in the 3-sphere.

2000 ◽  
Vol 31 (4) ◽  
pp. 289-296
Author(s):  
Tooru Sasahara

B. Y. Chen introduced in [3] an important Riemannian invariant for a Riemannian manifold and obtained a sharp inequality between his invariant and the squared mean curvature for arbitrary submanifolds in real space forms. In this paper we investigate 3-dimensional CR-submanifolds in the nearly Kaehler 6-sphere which realize the equality case of the inequality.


2004 ◽  
Vol 83 (4) ◽  
pp. 371-380
Author(s):  
Vicente Palmer ◽  
Mayte Pi�ero

2012 ◽  
Vol 64 (1) ◽  
pp. 44-80 ◽  
Author(s):  
T. M. M. Carvalho ◽  
H. N. Moreira ◽  
K. Tenenblat

AbstractWe consider the Randers space (Vn, Fb) obtained by perturbing the Euclidean metric by a translation, Fb = α + β, where α is the Euclidean metric and β is a 1-form with norm b, 0 ≤ b < 1. We introduce the concept of a hypersurface with constant mean curvature in the direction of a unitary normal vector field. We obtain the ordinary differential equation that characterizes the rotational surfaces (V3, Fb) of constant mean curvature (cmc) in the direction of a unitary normal vector field. These equations reduce to the classical equation of the rotational cmc surfaces in Euclidean space, when b = 0. It also reduces to the equation that characterizes the minimal rotational surfaces in (V3, Fb) when H = 0, obtained by M. Souza and K. Tenenblat. Although the differential equation depends on the choice of the normal direction, we show that both equations determine the same rotational surface, up to a reflection. We also show that the round cylinders are cmc surfaces in the direction of the unitary normal field. They are generated by the constant solution of the differential equation. By considering the equation as a nonlinear dynamical system, we provide a qualitative analysis, for . Using the concept of stability and considering the linearization around the single equilibrium point (the constant solution), we verify that the solutions are locally asymptotically stable spirals. This is proved by constructing a Lyapunov function for the dynamical systemand by determining the basin of stability of the equilibrium point. The surfaces of rotation generated by such solutions tend asymptotically to one end of the cylinder.


2012 ◽  
Vol 55 (3) ◽  
pp. 611-622 ◽  
Author(s):  
Cihan Özgür ◽  
Adela Mihai

AbstractIn this paper we prove Chen inequalities for submanifolds of real space forms endowed with a semi-symmetric non-metric connection, i.e., relations between the mean curvature associated with a semi-symmetric non-metric connection, scalar and sectional curvatures, Ricci curvatures and the sectional curvature of the ambient space. The equality cases are considered.


2004 ◽  
Vol 70 (1) ◽  
pp. 55-65 ◽  
Author(s):  
Bang-Yen Chen

We introduce a Riemannian invariant and establish general optimal inequalities involving the invariants and the squared mean curvature for Einstein manifolds isometrically immersed in real space forms. We show that these inequalities do not hold for arbitrary submanifolds in real space forms in general. We also provide some immediate applications of the inequalities.


1996 ◽  
Vol 38 (1) ◽  
pp. 87-97 ◽  
Author(s):  
Bang-Yen Chen

According to the well-known Nash's theorem, every Riemannian n-manifold admits an isometric immersion into the Euclidean space En(n+1)(3n+11)/2. In general, there exist enormously many isometric immersions from a Riemannian manifold into Euclidean spaces if no restriction on the codimension is made. For a submanifold of a Riemannian manifold there are associated several extrinsic invariants beside its intrinsic invariants. Among the extrinsic invariants, the mean curvature function and shape operator are the most fundamental ones.


1997 ◽  
Vol 56 (1) ◽  
pp. 37-49 ◽  
Author(s):  
J. Arroyo ◽  
M. Barros ◽  
O.J. Garay

We classify unit speed curves contained in a real space form of arbitrary dimension Nm(c), whose mean curvature vector is proper for the Laplacian. Then we use these results to classify Hopf cylinders of S3 and semi-Riemannian Hopf cylinders of with proper mean curvature function.


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