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.
Study degenerate Bianchi transformations for pseudo-spherical submanifolds in 5D space.
problem Characterize three-dimensional pseudo-spherical submanifolds with degenerate Bianchi transformations.
method Complete description through holonomically degenerate Bianchi transformations.
result Obtained a complete description of degenerate pseudo-spherical submanifolds.
Study pseudo-spherical submanifolds with 1-type Gauss map in pseudo-spheres.
problem Characterize and classify pseudo-Riemannian submanifolds with 1-type pseudo-spherical Gauss map.
method Classify Lorentzian surfaces and pseudo-Riemannian submanifolds in pseudo-spheres with 1-type pseudo-spherical Gauss map.
result Classification of submanifolds with 1-type pseudo-spherical Gauss map in pseudo-spheres.
The study characterizes compact submanifolds with pinched Ricci curvature in Euclidean and spherical space forms.
problem Characterizing compact submanifolds with specific Ricci curvature bounds.
method Proving rigidity results for submanifolds with Ricci curvature bounded below by a function of mean curvature.
result Submanifolds are either isometric to the Einstein Clifford torus or have vanishing homology groups up to a certain degree.
Study of spacelike submanifolds in spherical RW spacetime, proving a Lorentzian Takahashi theorem.
problem Characterizing stationary spacelike submanifolds in spherical RW spacetime.
method Embedding spherical RW spacetime in Lorentz-Minkowski spacetime, studying Lorentzian hypersurfaces, and applying results to submanifolds.
result Wide extension of Lorentzian Takahashi theorem for stationary spacelike submanifolds.
Study of free boundary minimal Möbius bands in spherical caps.
problem Characterizing minimal surfaces with free boundary in spherical caps.
method Analyzing spectral properties and geometric constraints.
result Proves that any free boundary minimal Möbius band in spherical caps must be intrinsically rotationally symmetric.
An isometric immersion f:Mn→M~n from a Riemannian n-manifold Mn into a Kähler n-manifold M~n is called {\it Lagrangian} if the complex structure J of the ambient manifold M~n interchanges each tangent space of Mn with the corresponding normal space. In this paper, we completel…
This paper classifies Kaehler submanifolds in hyperbolic space with low codimension.
problem Local classification of Kaehler submanifolds in hyperbolic space with low codimension.
method Intrinsic assumptions and extrinsic product of two-dimensional umbilical spheres in S^3n-1.
result Generalization of results for spherical submanifolds to hyperbolic ambient space.
Combining the tools of geometric analysis with properties of Jordan angles and angle space distributions, we derive a spherical and a Euclidean Bernstein theorem for minimal submanifolds of arbitrary dimension and codimension, under the condition that the Gauss image is contained in some geometrically defined closed re…
This is a short, elementary survey article about taut submanifolds. In order to simplify the exposition, we restrict to the case of compact smooth submanifolds of Euclidean or spherical spaces. Some new, partial results concerning taut 4-manifolds are discussed at the end of the text.
We obtain a blow-up theorem for regular submanifolds in the Heisenberg group, where intrinsic dilations are used. Main consequence of this result is an explicit formula for the density of (p+1)-dimensional spherical Hausdorff measure restricted to a p-dimensional submanifold with respect to the Riemannian surface measu…
We find all intrinsic measures of C1,1 smooth submanifolds in the Engel group, showing that they are equivalent to the corresponding d-dimensional spherical Hausdorff measure restricted to the submanifold. The integer d is the degree of the submanifold. These results follow from a different approach to negligi…
The geometry of symmetric spaces, polar actions, isoparametric submanifolds and spherical buildings is governed by spherical Weyl groups and simple Lie groups. A natural generalization of semisimple Lie groups are affine Kac-Moody groups as they mirror their structure theory and have good explicitely known representati…
We describe several families of Lagrangian submanifolds in the complex Euclidean space which are H-minimal, i.e. critical points of the volume functional restricted to Hamiltonian variations. We make use of various constructions involving planar, spherical and hyperbolic curves, as well as Legendrian submanifolds of th…
Study free boundary minimal submanifolds in geodesic balls in hyperbolic and spherical spaces.
problem Characterize free boundary minimal submanifolds in geodesic balls of hyperbolic and spherical spaces.
method Define and analyze functionals related to critical metrics and spectral indices.
result Critical metrics of defined functionals arise from free boundary minimal immersions in geodesic balls of hyperbolic and spherical spaces.
Sharp area estimates for minimal submanifolds in curved spaces.
problem Estimating the area of minimal submanifolds passing through a specific point.
method Proving sharp area estimates in hyperbolic and spherical spaces.
result Sharp area estimates analogous to Euclidean settings.
Quantum states are not entangled if submanifold is a product.
problem Understanding entanglement in quantum states associated with product submanifolds.
method Analyzing quantum states ρN on submanifolds of product Kähler manifolds in the semiclassical limit. result States are not entangled when submanifold is a product.
Study warped product metrics on hyperbolic and complex hyperbolic manifolds.
problem Understanding curvature of warped product metrics.
method Prove curvature formulas for warped product metrics on hyperbolic and complex hyperbolic manifolds.
result Curvature formulas expressed in spherical coordinates about totally geodesic submanifolds.
Horizontal points of smooth submanifolds in stratified groups play the role of singular points with respect to the Carnot-Carathe'odory distance. When we consider hypersurfaces, they coincide with the well known characteristic points. In two step groups, we obtain pointwise estimates for the Riemannian surface measure …
Sharp bounds for eigenfunctions on product spaces restricted to submanifolds.
problem Establishing bounds for eigenfunctions on product spaces.
method Combining asymptotics of Jacobi polynomials and positivity of Fourier coefficients of spherical functions.
result Sharp Lp bounds for eigenfunctions on products of rank-one symmetric spaces. For each submanifold of a stratified group, we find a number and a measure only depending on its tangent bundle, the grading and the fixed Riemannian metric. In two step stratified groups, we show that such number and measure coincide with the Hausdorff dimension and with the spherical Hausdorff measure of the submanif…
The classical Minkowski formula is extended to spacelike codimension-two submanifolds in spacetimes which admit "hidden symmetry" from conformal Killing-Yano two-forms. As an application, we obtain an Alexandrov type theorem for spacelike codimension-two submanifolds in a static spherically symmetric spacetime: a codim…
Tautness of submanifolds in spheres is preserved under Lie sphere transformations.
problem Invariance of tautness under Lie sphere transformations.
method Extending tautness definition to Legendre submanifolds and using Lie sphere transformations to show invariance.
result Tautness is invariant under Lie sphere transformations.
New proof shows minimal submanifolds of sphere are totally geodesic.
problem Characterize minimal submanifolds of spheres.
method Develops a new proof strategy.
result Obtains analogous result for codimension 2 minimal submanifolds.
During an operation of surgery on a Riemannian manifold and along a given embedded submanifold, one needs to replace the (old) metric induced by the exponential map on a tubular neighborhood of the submanifold by the Sasakian metric. So a good understanding of the behavior of these two metrics is important, this is our…
Weyl's tube formula holds for various cross-sections under symmetry conditions.
problem Can the volume of tubes around submanifolds be calculated for non-round cross-sections?
method Investigated the volume of tubes with general cross-sections D under symmetry conditions.
result The volume of tubes around submanifolds can be calculated for general cross-sections under symmetry conditions.
Study on quantum state entanglement using Kaehler manifolds.
problem Quantum state entanglement on Kaehler manifolds.
method Semiclassical asymptotics and pure states on spheres.
result Entropy analysis of quantum states on spheres.
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.
Tight isoparametric hypersurfaces in spheres have minimal critical points.
problem Finding minimal critical points on isoparametric hypersurfaces.
method Münzner's work on isoparametric hypersurfaces in spheres.
result Isoparametric hypersurfaces in spheres are tight.
Some new differentiable sphere theorems are obtained via the Ricci flow and stable currents. We prove that if Mn is a compact manifold whose normalized scalar curvature and sectional curvature satisfy the pointwise pinching condition R0>σnKmax, where σn∈(41,1) is an explicit positive constan…
Survey of rigidity and gap phenomena in sphere-ball submanifolds.
problem Rigidity and gap phenomena in submanifolds of sphere and ball.
method Comparison of techniques, pinching and gap theorems, Morse index and topology.
result Free boundary condition in ball forces stronger rigidity than in sphere.
Defines state sum models with defects in 3-manifolds.
problem Detecting and characterizing defects in 3-manifolds.
method Turaev-Viro-Barrett-Westbury state sum models with defects labeled by bimodule categories and functors.
result State sums are triangulation-independent and can be computed using polygon diagrams.
The paper projects unknown manifolds onto hyperspheres for efficient function approximation.
problem Function approximation from data on unknown manifolds with added errors.
method Projects unknown manifold onto hypersphere and uses localized spherical polynomial kernels.
result Optimal rates of approximation for rough functions are given.
We define a capacity which measures the size of Weinstein tubular neighbourhoods of Lagrangian submanifolds. In symplectic vector spaces this leads to bounds on the codisc radius for any closed Lagrangian submanifold in terms of Viterbo's isoperimetric inequality. Moreover, we prove a generalization of Gromov's packing…
Method estimates curvature of submanifolds using hypersurface integral invariants.
problem Estimating curvature of submanifolds in high dimensions.
method Integral invariants from PCA on hypersurface domains.
result Eigenvalues and eigenvectors as multi-scale curvature estimators.
In this paper, we establish universal inequalities for eigenvalues of the clamped plate problem on compact submanifolds of Euclidean spaces, of spheres and of real, complex and quaternionic projective spaces. We also prove similar results for the biharmonic operator on domains of Riemannian manifolds admitting spherica…
We use the terms, knot product and local move, as defined in the text of the paper. Let n be an integer≧3. Let Sn be the set of simple spherical n-knots in Sn+2. Let m be an integer≧4. We prove that the map j:S2m→S2m+4 is bijective, where j(K)=K⊗Hop…
T-PSDA improves speaker recognition accuracy on toroidal submanifolds.
problem Improving speaker recognition accuracy on hypersphere embeddings.
method Extends PSDA to model within and between-speaker variabilities in toroidal submanifolds of the hypersphere.
result T-PSDA achieves accuracy on par with cosine scoring on VoxCeleb and large accuracy gains on NIST SRE'21.
We consider a variational problem for submanifolds Q ⊂ M with nonempty boundary ∂Q = K. We propose the definition that the boundary K of any critical point Q have constant mean curvature, which seems to be a new perspective when dim Q \textless{} dim M . We then construct small nearly-spherical solutio…
The paper extends Liebmann's Theorem to convex hypersurfaces with boundary.
problem Proving properties of convex hypersurfaces with boundary in Euclidean space.
method Analyzing locally convex, embedded, compact, connected CMC hypersurfaces bounded by a closed strictly convex submanifold.
result Spherical caps are the only such hypersurfaces with non-zero constant mean curvature bounded by a (n−1)−sphere. Free boundary minimal submanifolds with boundaries on concentric spheres
problem Finding minimal submanifolds with boundaries on concentric spheres in Euclidean space
method Using a Steklov problem with an indefinite weight
result Exact Morse index of an m-dimensional flat annulus in an n-dimensional spherical shell Real torus in S2imesS2 not Hamiltonian isotopic to Clifford torus.
problem Characterize real Lagrangian submanifolds in symplectic manifolds.
method Maslov index 2 J-holomorphic discs, involutions, fixed point sets. result Chekanov torus in S2imesS2 is not real. We study special Lagrangian cones in $\C^n$ with isolated singularities. Our main result constructs an infinite family of special Lagrangian cones in $\C^3$ each of which has a toroidal link. We obtain a detailed geometric description of these tori. We prove a regularity result for special Lagrangian cones in $\C^3$ wi…
Study of homothetic solitons in inverse mean curvature flow.
problem Understanding the behavior of solitons in inverse mean curvature flow.
method Analyzing solutions that evolve by homotheties of a given submanifold.
result Classification of rotationally invariant Lagrangian homothetic solitons.
Study a relative aspherical conjecture and prove 3-manifold obstruction to positive scalar curvature.
problem Obstructing the existence of positive scalar curvature in higher dimensions.
method Introduced a relative aspherical condition and a new geometric quantity called spherical width.
result Proved results on how 3-manifolds obstruct the existence of positive scalar curvature.
This paper studies CR manifolds and embeddability in complex spaces.
problem Characterize embeddable deformations of 3D CR manifolds.
method Analyzes complex functions on CR manifolds and uses spherical harmonics.
result Space of embeddable deformations is a Frechet submanifold near the origin.
Stability of extremal Reissner-Nordström black holes proven in spherical symmetry.
problem Stability of extremal Reissner-Nordström black holes in spherical symmetry.
method Proved nonlinear asymptotic stability through spherically symmetric characteristic data.
result Existence of a submanifold Mstab leading to stable solutions. Study of families of lines on spheres and their focal sets.
problem Characterizing families of lines on spheres and their geometric properties.
method Analyzing submanifolds of TSn and their focal sets, using symplectic structures and sectional curvatures. result Derivation of formulas relating sectional curvatures of focal sets to differences in radii of curvature of generating hypersurfaces.