Study surfaces with constant ratio of principal curvatures in Euclidean and isotropic geometries.
problem Characterize surfaces with constant ratio of principal curvatures in different geometries.
method Differential geometry, line geometry, Lie sphere geometry, ordinary differential equations, algebraic geometry.
result Characterized various types of surfaces like rotational, channel, ruled, helical, and translational.
Study finds all helical surfaces with a constant ratio of principal curvatures.
problem Identifying helical surfaces with a constant ratio of principal curvatures.
method Employing the contours for parallel projection orthogonal to the helical axis, and solving an ordinary differential equation.
result Explicit CRPC surfaces beyond rotational ones are determined.
If M is an isoparametric hypersurface in a sphere Sn with four distrinct principal curvatures, then the principal curvatures κ1,...,κ4 can be ordered so that their multiplicities satisfy m1=m2 and m3=m4, and the cross-ratio r of the principal curvatures (the Lie curvature) equals -1. In this paper, w…
This research solves Plateau's problem for CRPC surfaces.
problem Constructing surfaces with constant ratio of principal curvatures.
method Proposed a family of surfaces containing a given minimal surface without flat points.
result Obtained a partial solution to Plateau's problem for CRPC surfaces.
Compact Dupin hypersurfaces without constant Lie curvatures found.
problem Finding compact Dupin hypersurfaces with non-constant Lie curvatures.
method Two constructions of compact proper Dupin hypersurfaces in Sn. result Examples of compact proper Dupin hypersurfaces without constant Lie curvatures.
We consider convex hypersurfaces for which the ratio of principal curvatures at each point is bounded by a function of the maximum principal curvature with limit 1 at infinity. We prove that the ratio of circumradius to inradius is bounded by a function of the circumradius with limit 1 at zero. We apply this result to …
The paper classifies and determines properties of specific hypersurfaces in complex hyperbolic quadrics.
problem Analyzing Hopf hypersurfaces with constant principal curvatures in complex hyperbolic quadrics.
method Classification and determination of principal curvatures for hypersurfaces with different numbers of distinct curvatures.
result Classification and determination of principal curvatures for Hopf hypersurfaces with up to four distinct values.
The study finds parametrizations for surfaces of revolution with a linear curvature ratio.
problem Deriving surfaces of revolution with a specific curvature ratio.
method Derives parametrizations for surfaces of revolution with an affine-linear relation between their curvature radii.
result Explicit parametrizations found for a countably-infinite number of surfaces.
Study on isoparametric and constant-curvature hypersurfaces in Finsler spaces.
problem Characterizing and constructing hypersurfaces with specific curvature properties in Finsler geometry.
method Analyzing isoparametric and constant-curvature hypersurfaces on Randers manifolds.
result Construction of a conformally flat Randers manifold with nonisoparametric hyperplanes of constant curvatures.
Study on discrete surfaces with constant principal curvature for nanocarbon applications.
problem Understanding discrete geometry properties of nanocarbon materials.
method Developed discrete surface theory on 3-ary oriented trees, defined discrete principal directions, constructed examples of discrete CPC surfaces.
result Construction of discrete constant principal curvature surfaces, including discrete CPC tori.
Similar to the definition of Dupin hypersurface in Riemannian space forms, we define the spacelike Dupin hypersurface in Lorentzian space forms. As conformal invariant objects, spacelike Dupin hypersurfaces are studied in this paper using the framework of conformal geometry. Further we classify the spacelike Dupin hype…
Study on curvature bounds for specific hypersurfaces in Anti-de Sitter space.
problem Bounding principal curvatures of constant mean curvature hypersurfaces.
method Generalized convex hull concept and quantitative estimates based on width.
result Explicit bounds on sectional curvature and quasiconformal dilatation.
The paper classifies Hopf hypersurfaces with constant curvatures on complex quadrics.
problem Classifying Hopf hypersurfaces with specific curvature properties.
method Analyzing hypersurfaces on complex quadrics with at most five distinct constant principal curvatures.
result All classified hypersurfaces are open parts of homogeneous examples.
We prove new pinching estimate for the inverse curvature flow of strictly convex hypersurfaces in the space form N of constant sectional curvature KN with speed given by F−α, where α∈(0,1] for KN=0,−1 and α=1 for KN=1, F is a smooth, symmetric homogeneous of degree one function which is inverse…
We classify all real hypersurfaces with constant principal curvatures in the complex hyperbolic plane.
We classify all real hypersurfaces with three distinct constant principal curvatures in complex hyperbolic spaces of dimension greater than two.
In this paper, we investigate the contracting curvature flow of closed, strictly convex axially symmetric hypersurfaces in Rn+1 and Sn+1 by σkα, where σk is the k-th elementary symmetric function of the principal curvatures and α≥1/k. We prove that for any n≥3 and any fixe…
The study classifies hypersurfaces with constant principal curvatures in S3imesR and H3imesR.
problem Classifying hypersurfaces with constant principal curvatures in specific product spaces.
method Analyzing isoparametric surfaces and using isoparametric properties to classify hypersurfaces.
result Hypersurfaces with constant principal curvatures are cylinders over isoparametric surfaces in Q3. We study surfaces with one constant principal curvature in Riemannian and Lorentzian three-dimensional space forms. Away from umbilic points they are characterized as one-parameter foliations by curves of constant curvature, each of these curves being centered at a point of a regular curve and contained in its normal p…
The paper classifies various types of hypersurfaces in a product space.
problem Classifying hypersurfaces in a specific product space.
method Analyzing hypersurfaces with constant curvatures, product angle functions, and additional conditions.
result Different types of hypersurfaces are classified based on their properties.
We classify the homogeneous and isoparametric hypersurfaces of S2×S2. In the classification, besides the hypersurfaces S1(r)×S2,r∈(0,1], it appears a family of hypersurfaces with three different constant principal curvatures and zero Gauss-Kronecker curvature. …
The study examines spacelike hypersurfaces in Minkowski space with constant σn−1 curvature.
problem Characterizing spacelike hypersurfaces with constant σn−1 curvature in Minkowski space. method Analyzing hypersurfaces with bounded principal curvatures and proving properties of their convexity.
result Hypersurfaces with constant σn−1 curvature in Minkowski space are either convex or can be split into a product form. We consider surfaces in Euclidean space parametrized on an annular domain such that the first fundamental form and the principal curvatures are rotationally invariant, and the principal curvature directions only depend on the angle of rotation (but not the radius). Such surfaces generalize the Enneper surface. We show …
We construct uncountably many isoparametric families of hypersurfaces in Damek-Ricci spaces. We characterize those of them that have constant principal curvatures by means of the new concept of generalized Kahler angle. It follows that, in general, these examples are inhomogeneous and have nonconstant principal curvatu…
In this note we construct an explicit example of a (compact) conformally flat Riemannian manifold which admits a totally geodesic foliation of codimension one with no isoparametric leaves. This answers negatively the question: is every hypersurface with constant principal curvatures isoparametric?
Classifies isoparametric hypersurfaces in 3D manifolds.
problem Identifying isoparametric hypersurfaces in specific 3D manifolds.
method By proving constant angle and principal curvatures.
result Established classification of hypersurfaces.
In this paper, we have studied biharmonic hypersurfaces in space form Mˉn+1(c) with constant sectional curvature c. We have obtained that biharmonic hypersurfaces Mn with at most three distinct principal curvatures in Mˉn+1(c) has constant mean curvature. We also obtain the full classificatio…
We classify real hypersurfaces in complex space forms with constant principal curvatures and whose Hopf vector field has two nontrivial projections onto the principal curvature spaces. In complex projective spaces such real hypersurfaces do not exist. In complex hyperbolic spaces these are holomorphically congruent to …
The paper studies Einstein hypersurfaces in a specific warped product space.
problem Investigating Einstein hypersurfaces in a warped product space.
method Analyzing the principal curvatures and using multiply warped product structure.
result Hypersurfaces have at most three distinct principal curvatures and are locally multiply warped products.
Novel symmetry found in nanocarbons' discrete principal curvature structure.
problem Identifying novel symmetries in nanocarbons' geometric structures.
method First-principles calculations and discrete geometry analysis.
result Discovery of a novel symmetry (pre-constant discrete principal curvature) in nanocarbons.
The paper classifies surfaces with constant curvature in 3D De Sitter and anti De Sitter spaces.
problem Classifying surfaces with constant curvature in 3D De Sitter and anti De Sitter spaces.
method Analyzing conditions equivalent to constant principal curvature, mean curvature, and second mean curvature.
result Surfaces of L1-2-type in De Sitter and anti De Sitter spaces are either standard products, scrolls, or have non-constant curvature properties. In this paper, we classify the hypersurfaces in Sn×R and Hn×R, n=3, with g distinct constant principal curvatures, g∈{1,2,3}, where Sn and Hn denote the sphere and hyperbolic space of dimension n, respectively. We prove…
Paper corrects a proof about biharmonic hypersurfaces with three distinct curvatures.
problem Proving constant mean curvature for biharmonic hypersurfaces with three distinct principal curvatures.
method Analyzing the resultant of polynomials to identify a special case.
result In the special case, the hypersurface still has constant mean curvature.
Let M be a closed minimal hypersurface in 5-dimensional Euclidean sphere with constant nonnegative scalar curvature. We prove that, if the sum of the cubes of all principal curvatures and the number of distinct principal curvatures are constant, then M is isoparametric. Moreover, We give all possible values for squared…
We study submanifolds whose principal curvatures, counted with multiplicities, do not depend on the normal direction. Such submanifolds, which we briefly call CPC submanifolds, are always austere, hence minimal, and have constant principal curvatures. Well-known classes of examples include totally geodesic submanifolds…
The study classifies hypersurfaces in quaternionic space forms with constant principal curvatures.
problem Classifying hypersurfaces in quaternionic space forms with specific curvature properties.
method Analyzing curvature-adapted real hypersurfaces in non-flat quaternionic space forms HPm and HHm. result Classification of hypersurfaces including geodesic hyperspheres, tubes, and specific examples in HPm and HHm. Paper finds conditions for minimal hypersurfaces in S^6 with constant scalar curvature.
problem Finding conditions for minimal hypersurfaces in S^6 with constant scalar curvature.
method Assumptions on principal curvatures for isoparametric hypersurfaces.
result Rigidity result: Hypersurfaces with exactly two distinct principal curvatures are Clifford tori.
New examples of hypersurfaces found in quaternionic hyperbolic spaces.
problem Classifying actions on symmetric spaces of rank one.
method Cohomogeneity one actions and orbit equivalence.
result Uncountably many inhomogeneous isoparametric families of hypersurfaces.
Complete classification of isoparametric hypersurfaces in product spaces of space forms.
problem Classifying isoparametric hypersurfaces in product spaces of space forms.
method Proving constant product angle function and removing constant principal curvatures condition.
result Complete classification of isoparametric hypersurfaces in product spaces of space forms.
In this paper, we obtain some properties of biconservative Lorentz hypersurface M1n in E1n+1 having shape operator with complex eigen values. We prove that every biconservative Lorentz hypersurface M1n in E1n+1 whose shape operator has complex eigen values with at most five distinct prin…
Lie minimal surfaces are characterized by differential equations of principal curvatures.
problem Characterizing Lie minimal surfaces in Riemannian space forms.
method Using Euler-Lagrange equations and differential equations of principal curvatures.
result Rotational surfaces are found for certain relationships between principal curvatures.
The study classifies isoparametric and homogeneous hypersurfaces in product spaces.
problem Classifying hypersurfaces in product spaces.
method Exploiting rigidity of constant angle functions and constant principal curvatures.
result Complete classification of isoparametric and homogeneous hypersurfaces in SnimesRm and HnimesRm. It is known that hypersurfaces in CPn or CHn for which the number g of distinct principal curvatures satisfied g≤2 must belong to a standard list of Hopf hypersurfaces with constant principal curvatures, provided that n≥3. In this paper, we construct a 2-parameter family of non-Hopf hypersurfaces in…
The paper constructs all cmc hypersurfaces with two principal curvatures.
problem Finding all hypersurfaces with constant mean curvature and two principal curvatures.
method Explicit immersions and parameter analysis for hypersurfaces in space forms.
result The family of cmc hypersurfaces with two principal curvatures depends on two parameters, H and C.
Study proves surfaces with constant curvature are simple shapes.
problem Characterizing singular minimal surfaces with constant curvature.
method Proved geometric properties of surfaces with constant curvature.
result Singular minimal surfaces with constant curvature are planes, spheres, and cylindrical surfaces.
The paper classifies hypersurfaces in a specific 4D geometry.
problem Classify homogeneous hypersurfaces in the four-dimensional Thurston geometry mSol04. method Used geometric conditions to classify hypersurfaces with constant principal curvatures.
result Complete classification of homogeneous hypersurfaces in mSol04. The study classifies isoparametric hypersurfaces in specific product spaces.
problem Classifying isoparametric hypersurfaces in product spaces.
method Analyzing the angle function and constant principal curvatures.
result A complete classification of isoparametric and homogeneous hypersurfaces in SnimesSm and SnimesHm. A hypersurface Mn−1 in a real space-form Rn, Sn or Hn is isoparametric if it has constant principal curvatures. For Rn and Hn, the classification of isoparametric hypersurfaces is complete and relatively simple, but as Elie Cartan showed in a series of four papers in 1938-1940, the subje…