Results 41 to 50 of about 17,898 (118)
Timelike Tangent Developable Surfaces and Bonnet Surfaces
Abstract and Applied Analysis, Volume 2016, Issue 1, 2016., 2016 A criterion was given for a timelike surface to be a Bonnet surface in 3‐dimensional Minkowski space by Chen and Li, 1999. In this study, we obtain a necessary and sufficient condition for a timelike tangent developable surface to be a timelike Bonnet surface by the aid of this criterion.
Soley Ersoy, Kemal Eren, Chun-Gang Zhu
wiley +1 more source
Totally umbilic null hypersurfaces in generalized Robertson–Walker spaces
Differential Geometry and its Applications, 2015 We show that there is a correspondence between totally umbilic null hypersurfaces in generalized Robertson-Walker spaces and twisted decompositions of the fibre. This allows us to prove that nullcones are the unique totally umbilic null hypersurfaces in the closed Friedmann Cosmological model.
Manuel Gutiérrez, Benjamín Olea
openaire +3 more sources
, 1992 It is well known that any complete hypersurface of Euclidean space is isometric with a sphere if it is umbilical and has non-vanishing mean curvature. Okumura ([2]) has studied totally umbilical hypersurfaces in a locally product Riemannian manifold.
Czesław Konopka
semanticscholar +1 more source
A Class of Special Hypersurfaces in Real Space Forms
Journal of Function Spaces, Volume 2016, Issue 1, 2016., 2016 We define the generalized golden‐ and product‐shaped hypersurfaces in real space forms. A hypersurface M in real space forms Rn+1, Sn+1, and Hn+1 is isoparametric if it has constant principal curvatures. Based on the classification of isoparametric hypersurfaces, we obtain the whole families of the generalized golden‐ and product‐shaped hypersurfaces ...
Yan Zhao, Ximin Liu, Hugo Leiva
wiley +1 more source
On totally umbilical and minimal surfaces of the Lorentzian Heisenberg groups
Mathematische Nachrichten, Volume 298, Issue 6, Page 1922-1942, June 2025.Abstract This paper has manifold purposes. We first introduce a description of the Gauss map for submanifolds (both spacelike and timelike) of a Lorentzian ambient space and relate the conformality of the Gauss map of a surface to total umbilicity and minimality.
Giovanni Calvaruso +2 more
wiley +1 more source
Multiplicative rectifying submanifolds of multiplicative Euclidean space
Mathematical Methods in the Applied Sciences, Volume 48, Issue 1, Page 329-339, 15 January 2025.In this paper, we initiate the study of the multiplicative Euclidean submanifolds, exhibiting the multiplicative counterparts of the Gauss–Weingarten formulas. Some particular types such as multiplicative conic, spherical, and totally geodesic submanifolds are analyzed.
Muhittin Evren Aydin +2 more
wiley +1 more source
Lightlike Hypersurfaces of Indefinite Generalized Sasakian Space Forms
Journal of Applied Mathematics, Volume 2015, Issue 1, 2015., 2015 We study lightlike hypersurfaces M of an indefinite generalized Sasakian space form M-(f1,f2,f3), with indefinite trans‐Sasakian structure of type (α, β), subject to the condition that the structure vector field of M- is tangent to M. First we study the general theory for lightlike hypersurfaces of indefinite trans‐Sasakian manifold of type (α, β ...
Dae Ho Jin, Dimitris Fotakis
wiley +1 more source
Constrained deformations of positive scalar curvature metrics, II
Communications on Pure and Applied Mathematics, Volume 77, Issue 1, Page 795-862, January 2024.Abstract We prove that various spaces of constrained positive scalar curvature metrics on compact three‐manifolds with boundary, when not empty, are contractible. The constraints we mostly focus on are given in terms of local conditions on the mean curvature of the boundary, and our treatment includes both the mean‐convex and the minimal case.
Alessandro Carlotto, Chao Li
wiley +1 more source
Time‐Dependent Evolving Null Horizons of a Dynamical Spacetime
International Scholarly Research Notices, Volume 2014, Issue 1, 2014., 2014 Totally geodesic null hypersurfaces have been widely used in the study of isolated black holes. In this paper, we introduce a new quasilocal notion of a family of totally umbilical null hypersurfaces called evolving null horizons (ENH) of a dynamical spacetime, satisfied under an appropriate energy condition.
K. L. Duggal +2 more
wiley +1 more source
The Morse Index of Sacks–Uhlenbeck α‐Harmonic Maps for Riemannian Manifolds
Journal of Mathematics, Volume 2024, Issue 1, 2024.In this paper, first we prove a nonexistence theorem for α‐harmonic mappings between Riemannian manifolds. Second, the instability of nonconstant α‐harmonic maps is studied with regard to the Ricci curvature criterion of their codomain. Then, we estimate the Morse index for measuring the degree of instability of some particular α‐harmonic maps ...
Amir Shahnavaz +3 more
wiley +1 more source