The study characterizes submanifolds in product spaces.
problem Limited studies on pseudo-umbilical submanifolds.
method Using projections from product structure, conditions for submanifolds to be invariant, anti-invariant, or semi-invariant are derived.
result Necessary and sufficient conditions for pseudo-umbilical submanifolds in locally product Riemannian manifolds.
The study proves that pseudo-umbilical spacelike submanifolds are totally geodesic and totally umbilical.
problem Characterizing properties of pseudo-umbilical spacelike submanifolds in indefinite space forms.
method Derived an intrinsic inequality and used it to show total geodesic property. Proved total umbilicity using Aiyama's result.
result Pseudo-umbilical spacelike submanifolds are totally geodesic and totally umbilical.
Totally geodesic Lagrangian submanifolds in nearly Kähler S³×S³.
problem Characterizing Lagrangian submanifolds in nearly Kähler manifolds.
method Analyzing H-umbilical properties and their implications for geodesicity. result In nearly Kähler S³×S³, H-umbilical Lagrangian submanifolds are totally geodesic. Minimal totally real submanifolds in complex space forms have special umbilical properties.
problem Characterizing minimal totally real submanifolds in complex space forms.
method Analyzing the position of umbilical normal vectors in the normal bundle.
result Pseudo-umbilical totally real submanifolds with flat normal connection in non-flat complex space forms are minimal.
Study umbilical properties of spacelike 2D submanifolds in semi-Riemannian geometry.
problem Characterize umbilical properties of spacelike 2D submanifolds.
method Introduce total shear tensor and shear operators; analyze relationships; consider novel umbilical notions; prove necessary and sufficient conditions for umbilical submanifolds.
result Unique umbilical direction exists unless submanifold is totally umbilical.
Study on umbilical submanifolds in specific geometric spaces.
problem Characterizing curvature properties of umbilical submanifolds.
method Analyzing totally and screen totally umbilical half lightlike submanifolds in almost contact B-metric manifolds.
result Curvature properties of these submanifolds were studied and characterized.
Defines conditions for umbilical submanifolds in arbitrary dimensions.
problem Conditions for umbilical submanifolds in arbitrary dimensions.
method Using the total shear tensor and defining shear and umbilical spaces.
result The sum of dimensions of shear and umbilical spaces equals the co-dimension.
Study classifies submanifolds in probability simplex.
problem Classifying submanifolds in the probability simplex.
method Complete classification through geometric analysis.
result Doubly totally-umbilical submanifolds identified and classified.
The purpose of this paper is to classify totally umbilical slant submanifolds of a Kenmotsu manifold. We prove that a totally umbilical slant submanifold M of a Kenmotsu manifold Mˉ is either invariant or anti-invariant or dimM=1 or the mean curvature vector H of M lies in the invariant normal subbundle.…
The notion of Lagrangian H-umbilical submanifolds was introduced by B. Y. Chen in 1997, and these submanifolds have appeared in several important problems in the study of Lagrangian submanifolds from the Riemannian geometric point of view. Recently, the author introduced the notion of tangentially biharmonic submanif…
Classifies special submanifolds in geometric spaces.
problem Classifying submanifolds in (κ,μ)-spaces. method Explicit construction and proof of properties.
result Submanifolds are limited to specific examples.
The paper classifies submanifolds in pseudo-Riemannian space forms.
problem Characterizing and classifying totally umbilical submanifolds.
method Classification of congruent classes of totally umbilical submanifolds in non-flat pseudo-Riemannian space forms.
result Some moduli spaces of isometric immersions between space forms are non-Hausdorff.
The paper studies minimal submanifolds with specific curvature properties in Euclidean space.
problem Minimal submanifolds with (n−2)-umbilical properties in Euclidean space. method Established a correspondence and developed a Weierstrass type method for local parametrization.
result Minimal, generic, (n−2)-umbilic submanifolds are (n−2)-rotational and have a parametric description. Study of spacelike submanifolds with umbilical lightlike normals in Lorentzian spacetimes.
problem Geometric and topological constraints on codimension-two spacelike submanifolds.
method Analysis of submanifolds with umbilical lightlike normal directions, using geometric and topological constraints.
result Any such submanifold is contained in a lightlike hypersurface, which is totally umbilical if the lightlike normal direction is umbilical.
Classification of umbilical submanifolds in a specific Riemannian product space.
problem Classifying umbilical submanifolds in the product space HkimesSn−k+1. method Analyzing the conformally flat product space and using geometric properties to classify submanifolds.
result There exists a p-parameter family of umbilical submanifolds with codimension at most $\mbox{min}\,\{k+1, n-k+2\}$. The authors obtained the classification theorem for Lagrangian H-umbilical submanifolds in quaternion Euclidean spaces using the idea of quaternion extensors.
Study on hemi-slant submanifolds in nearly Kaehler manifolds.
problem Characterizing hemi-slant submanifolds in nearly Kaehler manifolds.
method Integrability of distributions and cohomology class analysis.
result Results on totally umbilical hemi-slant submanifolds.
New classification of spherical 2-Dupin submanifolds.
problem Characterizing spherical 2-Dupin submanifolds.
method Analyzing properties of submanifolds in space forms.
result Classification of 2-Dupin submanifolds in space forms.
Using the idea of special Legendre curves, the authors obtained the explicit description of flat Lagrangian H-umbilical submanifolds in quaternion Euclidean spaces.
Study on null helices in semi-Riemannian manifolds with special submanifolds.
problem Investigating geometric properties of null helices on totally umbilical submanifolds in 3D semi-Riemannian manifolds.
method Using the null Frenet frame and degenerate metric condition, equations and invariants characterizing null helices are derived.
result Equations and invariants characterizing null helices on totally umbilical submanifolds in 3D semi-Riemannian manifolds are obtained.
New inequality shows all special submanifolds in light cone are totally umbilical spheres.
problem Characterizing submanifolds with parallel mean curvature in Lorentz-Minkowski spacetime.
method Established an integral inequality and used it to derive a rigidity result.
result All compact submanifolds with parallel mean curvature in light cone are totally umbilical spheres.
Study characterizes geometric properties of QGCR-null submanifolds in cosymplectic manifolds.
problem Characterizing geometric properties of QGCR-null submanifolds in cosymplectic manifolds.
method Characterization through totally umbilical and irrotational properties, and discussion of geodesity conditions.
result Characterizes geometric properties of ascreen QGCR-null submanifolds.
In [2] we have classified the Blaschke quasi-umbilical submanifolds in the conformal space Qsn. In this paper we shall classify the Blaschke para-umbilical hypersurfaces in the conformal space Qsn. That may be also considered as the extension of the classification of the conformal isotropic …
Study on CR-lightlike submanifolds in golden semi-Riemannian manifolds.
problem Exploring properties of CR-lightlike submanifolds in golden semi-Riemannian manifolds.
method Definition and investigation of properties of geodesic CR-submanifolds.
result Obtained results for totally geodesic and totally umbilical CR-submanifolds.
Totally geodesic submanifolds in spheres have restricted curvature properties.
problem Characterizing submanifolds in spheres based on curvature conditions.
method Analyzing normal curvature, scalar curvature, and second fundamental form conditions.
result Compact pseudo-umbilical submanifolds in spheres are totally geodesic under specific curvature conditions.
Study of holomorphic submanifolds in hypercomplex manifolds with specific metrics.
problem Characterizing holomorphic submanifolds in hypercomplex manifolds with Hermitian and Norden metrics.
method Investigation of necessary and sufficient conditions for total umbilicity and geodesicity.
result Conditions for holomorphic submanifolds to be totally umbilical or totally geodesic are derived.
Paper studies CR submanifolds in complex projective space with flat normal connection.
problem Existence and properties of CR submanifolds with flat normal connection.
method Investigation of umbilical normal vector and application to non-existence proof.
result Non-existence of certain CR submanifolds of maximal CR dimension.
Study calculates total mean curvatures of specific submanifolds.
problem Calculating total mean curvatures of foliated half-lightlike submanifolds.
method Derived integration formulae and generalized differential equations.
result Generalized differential equations relating mean curvatures.
This paper classifies flat submanifolds with a special type of curvature form.
problem Classifying flat submanifolds with a specific curvature property.
method Using Moebius geometry and curvature operators to classify submanifolds.
result Classification of umbilic-free isometric immersions with flat normal bundle and semi-parallel Moebius second fundamental form.
Given the Lagrangian fibration T4→T2 and a Lagrangian submanifold, exhibiting an elliptic umbilic and supporting a flat line bundle, we study, in the context of mirror symmetry, the ``quantum'' corrections necessary to solve the monodromy of the holomorphic structure of the mirror bundle on the dual fibration.
The paper classifies submanifolds in a specific Lorentz-Minkowski space.
problem Characterizing submanifolds in a Lorentz-Minkowski space.
method Constructing a global frame field and analyzing extrinsic invariants.
result Local classification theorems for specific submanifold classes.
The paper studies the affine focal set of submanifolds in hypersurfaces, describing conditions for regularity and singularities.
problem Understanding the structure and properties of affine focal sets of submanifolds in hypersurfaces.
method Analyzing the bifurcation set of the affine distance, defining the affine metric and normal plane bundle, and proving properties of the g-Laplacian. result Conditions for the regularity and singularities of the affine focal set, including descriptions for specific cases like hyperplanes and hyperquadrics.
We give a complete classification of umbilical submanifolds of arbitrary dimension and codimension of $\Sf^n\times \R$, extending the classification of umbilical surfaces in $\Sf^2\times \R$ by Rabah-Souam and Toubiana as well as the local description of umbilical hypersurfaces in $\Sf^n\times \R$ by Van der Veken and …
We give a complete classification of submanifolds with parallel second fundamental form of a product of two space forms. We also reduce the classification of umbilical submanifolds with dimension m≥3 of a product $\Q_{k_1}^{n_1}\times \Q_{k_2}^{n_2}$ of two space forms whose curvatures satisfy k1+k2=0 to …
We give necessary and sufficient conditions for Riemannian maps to be biharmonic. We also define pseudo umbilical Riemannian maps as a generalization of pseudo-umbilical submanifolds and show that such Riemannian maps put some restrictions on the base manifolds.
Study totally umbilic submanifolds using planar pseudo-geodesics.
problem Characterize totally umbilic isometric immersions with parallel normalized mean curvature vector.
method Introduce planar pseudo-geodesics and analyze their properties; prove the equivalence of totally umbilic immersions and planar geodesic extrinsic shapes.
result An isometric immersion is totally umbilic if and only if every geodesic of the manifold has planar extrinsic shape.
Study of CR-submanifolds in various Lorentzian manifolds.
problem Exploring CR-submanifolds in different Lorentzian structures.
method Analyzing properties and results of CR-submanifolds in LCS, LP-cosymplectic, S, and GKM manifolds.
result Obtained results on totally umbilical and geodesic CR-submanifolds.
We call indexed-biharmonic maps, the solutions of a particular non linear elliptic PDE of order 4. This is a generalization of harmonic maps which verifies that biharmonic maps are biharmonic of index 0. The goal of this article is to study submanifolds of Sn whose inclusion is non harmonic and indexed-biha…
Several characterizations of umbilic points of submanifolds in arbitrary Riemannian and Lorentzian manifolds are given. As a consequence, we obtain new characterizations of spheres in the Euclidean space and of hyperbolic spaces in the Lorentz-Minkowski space. We also prove the Lorentzian version of a classical result …
The paper estimates eigenvalues of submanifolds in symmetric spaces.
problem Estimating eigenvalues of submanifolds in symmetric spaces.
method Combining spherical embeddings and conformal test-function arguments.
result Sharp estimates for the second eigenvalue of submanifolds in symmetric spaces.
We classify biharmonic submanifolds with certain geometric properties in Euclidean spheres. For codimension 1, we determine the biharmonic hypersurfaces with at most two distinct principal curvatures and the conformally flat biharmonic hypersurfaces. We obtain some rigidity results for pseudo-umbilical biharmonic subma…
A structure on an almost contact metric manifold is defined as a generalization of well-known cases: Sasakian, quasi-Sasakian, Kenmotsu and cosymplectic. Then we consider a semi-invariant ξ⊥-submanifold of a manifold endowed with such a structure and two topics are studied: the integrability of distributions de…
Study of f-biharmonic hypersurfaces in conformally flat spaces.
problem Characterize f-biharmonic hypersurfaces in conformally flat spaces. method Analyze f-biharmonicity of totally umbilical hypersurfaces in various contexts. result Properties of f-biharmonic hypersurfaces in nonpositively curved manifolds. Rigidity for 4D Willmore submanifolds with boundary.
problem Understanding critical points of Willmore energy with boundary conditions.
method Proving a 4-Willmore equation and establishing curvature estimates.
result Four dimensional Willmore submanifolds with totally geodesic boundary are umbilic.
Degenerate submanifolds of pseudo-Riemannian manifolds are quite difficult to study because there is no prefered connection when the submanifold is not totally geodesic. For the particular case of degenerate totally umbilical hypersurfaces, we show that there are "Weyl" connections adapted to the induced structure on t…
In this article we study isometric immersions of nearly Kähler manifolds into a space form (specially Euclidean space) and show that every nearly Kähler submanifold of a space form has a totally umbilic foliation whose leafs are 6-dimensional nearly Kähler manifolds. Moreover using this foliation we show that there is …
In this paper, we derived biharmonic equations for pseudo-Riemannian submanifolds of pseudo-Riemannian manifolds which includes the biharmonic equations for submanifolds of Riemannian manifolds as a special case. As applications, we proved that a pseudo-umbilical biharmonic pseudo-Riemannian submanifold of a pseudo-Rie…
Introduces new lightlike submanifolds in indefinite Kaehler manifolds.
problem Characterizing and understanding new types of lightlike submanifolds.
method Definition and analysis of Screen Transversal Cauchy Riemann (STCR) lightlike submanifolds.
result Characterizes STCR lightlike submanifolds as umbrella of other types.