The study characterizes Clifford hypersurfaces in terms of curvature constants.
problem Characterizing Clifford hypersurfaces in terms of curvature constants.
method Defined constants σ_k and used integral inequalities to show bounds on curvature.
result For specific conditions, σ_k ≥ n^k, with equality for Clifford hypersurfaces.
The paper studies inhomogeneous isoparametric hypersurfaces in pseudo-spheres.
problem Investigating inhomogeneous isoparametric hypersurfaces in pseudo-sphere.
method Construction of Clifford systems and analysis of isoparametric hypersurfaces.
result Connected isoparametric hypersurfaces of OT-FKM-type in pseudo-spheres are inhomogeneous under specific conditions.
We characterize the first min-max width of real projective spaces of any dimension. The width is the minimum area over the Clifford hypersurfaces. We also compute the Morse index of the Clifford hypersurfaces in the complex and quaternionic projective spaces.
The paper explores CMC hypersurfaces in spheres, verifying Yau's conjecture.
problem Exploring the space of CMC hypersurfaces in spheres.
method Description and verification of CMC hypersurfaces, focusing on H=0 cases. result Verification of Yau's conjecture for minimal hypersurfaces in spheres.
Study on minimal hypersurfaces in a unit sphere, proving specific isometries.
problem Characterizing minimal hypersurfaces with constant scalar curvature.
method Analyzing n-dimensional complete minimal hypersurfaces in a unit sphere with constant scalar curvature. result Proves isometry to totally geodesic sphere or Clifford torus under certain conditions.
Sharp focal radius estimate for hypersurfaces in manifolds with positive curvature.
problem Estimating the focal radius of hypersurfaces in manifolds with positive curvature.
method Proved a sharp Clifford-threshold focal-radius estimate and rigidity under specific curvature conditions.
result Any closed two-sided immersion satisfies a focal radius estimate of π/4, with equality case rigid.
Four constructions of constant mean curvature (CMC) hypersurfaces in the (n+1)-sphere are given, which should be considered analogues of `classical' constructions that are possible for CMC hypersurfaces in Euclidean space. First, Delaunay-like hypersurfaces, consisting roughly of a chain of hyperspheres winding multipl…
The paper proves conditions for closed minimally immersed hypersurfaces in a 5-sphere.
problem Conditions for closed minimally immersed hypersurfaces in a 5-sphere.
method Analyzes hypersurfaces with constant scalar curvature and A3. result Closed minimally immersed hypersurfaces in a 5-sphere are isoparametric and can only have specific scalar curvature values.
In this paper, we show that the catenoids and the Clifford minimal hypersurfaces are the only complete minimal hypersurfaces satisfying the Simons' equation (3.9) in the space forms.
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.
Using representations of Clifford algebras we construct indecomposable singular Riemannian foliations on round spheres, most of which are non-homogeneous. This generalizes the construction of non-homogeneous isoparametric hypersurfaces due to by Ferus, Karcher and Munzner.
Paper characterizes a special hypersurface in 5D sphere.
problem Characterizing minimal hypersurfaces in S5. method Analyzes hypersurfaces satisfying a specific curvature condition.
result Closed minimal hypersurfaces in S5 satisfying a certain curvature condition are either totally geodesic or congruent to the Cartan minimal hypersurface. The (n+1)-sphere contains a simple family of constant mean curvature (CMC) hypersurfaces which are products of lower-dimensional spheres called the generalized Clifford hypersurfaces. This paper demonstrates that new, topologically non-trivial CMC hypersurfaces resembling a pair of neighbouring generalized Clifford tor…
Study on free-boundary CMC hypersurfaces in upper hemisphere, proving Morse index and eigenvalue bounds.
problem Analyzing the Morse index and eigenvalues of free-boundary CMC hypersurfaces in the upper hemisphere.
method Proved results using the norm squared of the second fundamental form and eigenvalue estimates.
result Proved bounds on Morse index and eigenvalues for free-boundary CMC hypersurfaces.
Based on representation theory of Clifford algebra, Ferus, Karcher and Münzner constructed a series of isoparametric foliations. In this paper, we will survey recent studies on isoparametric hypersurfaces of OT-FKM type and investigate related geometric constructions with mean curvature flow.
Study proves mean curvature flows on spheres in higher dimensions.
problem Existence of mean curvature flows on spheres.
method Generalized previous results to higher dimensions, proving existence of flows.
result Existence of infinitely many eternal weak mean curvature flows in Sn+1 connecting specific hypersurfaces. Study on Gehring link problem and width of bands in curved manifolds.
problem Width of bands in positively curved manifolds.
method Same idea applied to focal radius and rigidity of hypersurfaces.
result Sphere theorem for hypersurfaces in Sn involving focal radius and rigidity of Clifford hypersurface. The study characterizes embedded minimal hypersurfaces in Sn+1 with symmetries.
problem Characterizing embedded minimal hypersurfaces in Sn+1 with specific symmetries. method Generalizing a characterization of the Clifford torus, the authors prove a Simons' type theorem and estimate the Willmore energy.
result The average of the square of the second fundamental form of an embedded minimal hypersurface is at least n with equality only for the Clifford torus. Paper proves minimal hypersurface index for specific cases.
problem Minimal hypersurface index estimation in Sn+1. method Comparison theorem between eigenvalues of elliptic operators.
result Minimal hypersurface index at least n+4 for λ1<n. Classifies hypersurfaces with constant isotropic curvature in space forms.
problem Identifying hypersurfaces with constant isotropic curvature in space forms.
method Analyzing complete orientable hypersurfaces and their properties.
result Hypersurfaces have constant mean curvature only if they are isoparametric, and are minimal under specific conditions.
We study conformally flat hypersurfaces $f\colon M^{3} \to \Q^{4}(c)$ with three distinct principal curvatures and constant mean curvature H in a space form with constant sectional curvature c. First we extend a theorem due to Defever when c=0 and show that there is no such hypersurface if H=0. Our main res…
Constructs CMC hypersurfaces in S^4 from piecewise-smooth unions of spheres.
problem Creating smooth CMC hypersurfaces from piecewise-smooth unions of spheres.
method Gluing totally umbilical 3-spheres to specific Clifford hypersurfaces, forming a smooth one-parameter family of CMC hypersurfaces.
result Desingularization of piecewise-smooth hypersurfaces yields smooth CMC hypersurfaces with embedded and non-embedded types.
Let φ:M→Sn+1⊂Rn+2 be an immersion of a complete n-dimensional oriented manifold. For any v∈Rn+2, let us denote by ℓv:M→R the function given by ℓv(x)=φ(x),v and by fv:M→R, the function given by fv(x)=ν(x),v, where $ν:M\to\mathbb{…
Using a new estimate for the Peng-Terng invariant and the multiple-parameter method, we verify a rigidity theorem on the stronger version of Chern Conjecture for minimal hypersurfaces in spheres. More precisely, we prove that if M is a compact minimal hypersurface in Sn+1 whose squared length of the sec…
The paper constructs metrics with non-negative curvature and harmonic maps.
problem Constructing metrics with non-negative curvature and harmonic maps.
method Using Clifford systems and characteristic maps, the paper constructs metrics with non-negative curvature and harmonic representatives of certain elements in homotopy groups of spheres.
result The construction of a metric of non-negative curvature on S(η) which is diffeomorphic to the inhomogeneous focal submanifold M+ of OT-FKM type isoparametric hypersurfaces. We construct biharmonic real hypersurfaces and Lagrangian submanifolds of Clifford torus type in CPn via the Hopf fibration; and get new examples of biharmonic submanifolds in S2n+1 as byproducts .
Proves rigidity in product spaces using index theory.
problem Scalar curvature rigidity in product spaces.
method Fredholm family index theorem.
result Recover corresponding results of Clifford-linear index theory.
For a compact minimal hypersurface M in Sn+1 with the squared length of the second fundamental form S we confirm that there exists a positive constant $\de(n)$ depending only on n, such that if n≤S≤n+δ(n), then S≡n, i.e., M is a Clifford minimal hypersurface, in particular, when $n\ge 6,…
Constructs minimal hypersurfaces in S^4(1) by doubling equatorial S^3.
problem Constructing minimal hypersurfaces in S^4(1).
method PDE gluing methods and Linearized Doubling (LD) methodology.
result Minimal hypersurfaces ${reve{M}_m}$ doubling the equatorial S^3 in S^4(1).
We provide explicit spinor representations for Clifford algebras.
problem Building explicit representations of Clifford algebras.
method Explicit construction of spinor modules and parallel spinor fields.
result Explicit spinor representations for all mixed signature Clifford algebras.
We obtain a complete classification of proper biharmonic hypersurfaces with at most three distinct principal curvatures in sphere spaces with arbitrary dimension. Precisely, together with known results of Balmuş-Montaldo-Oniciuc, we prove that compact orientable proper biharmonic hypersurfaces with at most three distin…
Let M⊂Sn+1⊂Rn+2 be a compact minimal hypersurface of the n-dimensional Euclidean unit sphere. Let us denote by ∣A∣2 the square of the norm of the second fundamental form and J(f)=−Δf−nf−∣A∣2f the stability operator. It is known that the index (the number of negative eigenvalues of …
The study examines stability of triharmonic hypersurfaces in space forms.
problem Stability of triharmonic hypersurfaces in space forms.
method Derivation of general stability statements, focus on specific cases of constant mean curvature in Euclidean and hyperbolic spaces, and analysis of small proper triharmonic hyperspheres and Clifford tori.
result Triharmonic hypersurfaces of constant mean curvature in Euclidean space are weakly stable with respect to normal variations, while in hyperbolic space they are stable.
A well-known conjecture of Yau states that the area of one of Clifford minimal hypersurfaces $S^k\big{(}\sqrt{\frac{k}{n}}\, \big{)}\times S^{n-k}\big{(}\sqrt{\frac{n-k}{n}}\, \big{)}$ gives the lowest value of area among all non-totally geodesic compact minimal hypersurfaces in the unit sphere Sn+1(1). The presen…
The paper proves properties of specific hypersurfaces in a 5-sphere.
problem Characterizing closed minimal hypersurfaces with constant curvature.
method Analyzing the curvature properties and using isoparametric functions.
result Closed minimal hypersurfaces in S5(1) have specific forms. 1. Translated by Thomas E. Cecil, Department of Mathematics and Computer Science, College of the Holy Cross, Worcester, MA 01610, USA; E-mail address: cecil@mathcs.holycross.edu 2. Typed by Wenjiao Yan, School of Mathematical Sciences, Laboratory of Mathematics and Complex Systems, Beijing Normal University, Beijing 10…
The study characterizes hypersurfaces in spheres with constant scalar curvature.
problem Characterizing hypersurfaces in spheres with constant scalar curvature.
method Combining intrinsic and extrinsic geometry, establishing Takahashi-type theorems, and deriving integral inequalities.
result Characterizes hypersurfaces with specific curvature properties and provides spherical Bernstein theorems.
In this paper we study Clifford and harmonic analysis on some conformal flat spin manifolds. In particular we treat manifolds that can be parametrized by U/Γ where U is a simply connected subdomain of either Sn or Rn and Γ is a Kleinian group acting discontinuously on U. Examples of such manifolds t…
In this work we characterize certain immersed closed hypersurfaces of some ambient manifolds via the second eigenvalue of the Jacobi operator. First, we characterize the Clifford torus as the surface which maximizes the second eigenvalue of the Jacobi operator among all closed immersed orientable surfaces of $\mathbb S…
Estimates the first eigenvalue of a Schrödinger operator on minimal submanifolds.
problem Estimating the first eigenvalue of a Schrödinger operator on minimal submanifolds.
method Analyzes the Schrödinger operator L:=−Δ−σ on minimal submanifolds Mn in the unit sphere Sn+m. result Provides an estimate for the first eigenvalue of the Schrödinger operator.
In this paper, two sequences of minimal isoparametric hypersurfaces are constructed via representations of Clifford algebras. Based on these, we give estimates on eigenvalues of the Laplacian of the focal submanifolds of isoparametric hypersurfaces in unit spheres. This improves results of [TY13] and [TXY14]. Eells and…
Let M be an isoparametric hypersurface in the sphere Sn with four distinct principal curvatures. Münzner showed that the four principal curvatures can have at most two distinct multiplicities m1,m2, and Stolz showed that the pair (m1,m2) must either be (2,2), (4,5), or be equal to the multiplicities o…
The study of conformal biharmonic maps and hypersurfaces in various spaces.
problem Understanding the properties and behavior of conformal biharmonic maps and hypersurfaces.
method Investigation of the conformal bienergy functional and its critical points, focusing on hypersurfaces in spheres and hyperbolic spaces.
result Identification and classification of conformal biharmonic hypersurfaces in spheres and hyperbolic spaces, including stability analysis.
The paper proves the regularity of cohomogeneity two problems and constructs minimal hypersurfaces on spheres.
problem Cohomogeneity two equivariant isotopy minimization problems and minimal hypersurfaces with large Betti numbers.
method Developed cohomogeneity two equivariant min-max theory for minimal hypersurfaces.
result Constructs minimal hypersurfaces on spheres with large Betti numbers and specific symmetries.
The paper studies inverse mean curvature flow on hypersurfaces in space forms.
problem Analyzing the inverse mean curvature flow on hypersurfaces in space forms.
method Investigates the existence and properties of the flow for isoparametric hypersurfaces.
result Characterizes the flow and solutions explicitly under certain conditions.
We verify that if M is a compact minimal hypersurface in Sn+1 whose squared length of the second fundamental form satisfying 0≤∣A∣2−n≤22n, then ∣A∣2≡n and M is a Clifford torus. Moreover, we prove that if M is a complete self-shrinker with polynomial volume growth in $\ma…
Motivated by the celebrated Schoen-Yau-Gromov-Lawson surgery theory on metrics of positive scalar curvature, we construct a double manifold associated with a minimal isoparametric hypersurface in the unit sphere. The resulting double manifold carries a metric of positive scalar curvature and an isoparametric foliation …
Sharp pinching theorem for submanifolds in spheres.
problem Characterizing submanifolds in spheres based on curvature bounds.
method Conformal method of Fischer-Colbrie, Shen & Ye and Catino, Mastrolia & Roncoroni.
result Complete submanifolds with specific curvature bounds are either totally geodesic or Clifford tori/Veronese surfaces.