In this paper, we study normal homogeneous Finsler spaces. We first define the notion of a normal homogeneous Finsler space, using the method of isometric submersion of Finsler metrics. Then we study the geometric properties. In particular, we establish a technique to reduce the classification of normal homogeneous Fin…
Survey on positively curved homogeneous Finsler spaces.
problem Classifying positively curved homogeneous Finsler spaces.
method Classification and related topics.
result Presentation of open problems in the field.
The paper extends a classical result to positively curved homogeneous spaces.
problem Classical results on constant functions on spheres do not extend to all positively curved homogeneous spaces.
method Proving that Lipschitz functions on positively curved homogeneous spaces are almost constant on high-dimensional submanifolds.
result Lipschitz functions on positively curved homogeneous spaces are almost constant on high-dimensional submanifolds.
Ricci flow preserves positive sectional curvature on homogeneous spheres
problem Classification of positively curved metrics on homogeneous spaces
method Proving Ricci flow preserves positive sectional curvature on homogeneous spheres
result Completes classification of positively curved metrics on homogeneous spaces
Paper classifies positively curved δ-homogeneous Finsler metrics.
problem Classifying positively curved Finsler metrics.
method Exploring δ-homogeneity and using approximation techniques.
result Classification of positively curved δ-homogeneous Finsler spaces.
Establishes metrics with positive 2nd intermediate Ricci curvature on products of curved spaces.
problem Examines the limitations of positive curvature metrics on product spaces.
method Uses examples to show Ric2>0 does not imply positive curvature for products of spaces. result The Ric2>0 class of manifolds is distinct from positively curved manifolds. In this paper, we use the flag curvature formula for homogeneous Finsler spaces in our previous work to classify odd dimensional smooth coset spaces admitting positively curved reversible homogeneous Finsler metrics. We will show that the most features of L. Bérard-Bergery's classification results for odd dimensional p…
The paper proves rigidity results for non-positively curved homogeneous Finsler metrics.
problem Rigidity of non-positively curved homogeneous Finsler metrics.
method Analyzes and proves rigidity results for specific Finsler metrics with non-positive flag curvature.
result Homogeneous Finsler spaces with non-positive flag curvature and isotropic S-curvature are either Riemannian or locally Minkowskian.
In this paper, we introduce the flag-wise positively curved condition for Finsler spaces (the (FP) Condition), which means that in each tangent plane, we can find a flag pole in this plane such that the corresponding flag has positive flag curvature. Applying the Killing navigation technique, we find a list of compact …
We examine homogeneous metrics on spheres and determine which ones have positive sectional curvature. The answer is subtle and surprisingly difficult to prove. In some cases we also determine their pinching constants. This completes the classification of all homogeneous metrics with positive curvature (apart from one s…
A Finsler space (M,F) is called flag-wise positively curved, if for any x∈M and any tangent plane P⊂TxM, we can find a nonzero vector y∈P, such that the flag curvature KF(x,y,P)>0. Though compact positively curved spaces are very rare in both Riemannian and Finsler g…
We study the topology of the 13 dimensional positively curved Bazaikin spaces. We show that there is only one such manifold which is homotopy equivalent to a homogeneous space, the so called Berger space. This is in contrast to the case of the 7 dimensional positively curved Eschenburg spaces. In addition, we compute t…
New proof for curved 3-cohom manifold rational ellipticity.
problem Rational ellipticity of curved manifolds with specific cohomogeneity.
method Proved rationally elliptic for cohomogeneity-three manifolds with positive curvature and no boundary quotient.
result Closed, simply connected, positively curved, cohomogeneity-three manifolds without boundary are rationally elliptic.
Linear inequality found for certain curved spaces.
problem Finding isoperimetric inequalities for curved spaces.
method Extending known result to homogeneous Hadamard manifolds.
result Linear isoperimetric inequality proven for higher-dimensional cycles.
The paper classifies compact homogeneous Finsler manifolds with positive flag curvature.
problem Classifying compact homogeneous Finsler manifolds with positive flag curvature.
method Defined and classified very standard homogeneous Finsler metrics on compact homogeneous Lie groups.
result Classified all compact homogeneous Lie groups admitting positively curved very standard homogeneous Finsler metrics.
New manifolds found with almost everywhere positive curvature.
problem Finding manifolds with positive curvature almost everywhere.
method Constructing manifolds in specific dimensions.
result Infinitely many new examples of manifolds with positive curvature almost everywhere.
The study finds that certain curved manifolds can be mapped to symmetric spaces.
problem Understanding singular Riemannian foliations in positively curved manifolds.
method Generalizing fixed point homogeneous actions to singular Riemannian foliations.
result Positively curved manifolds with point leaf maximal SRF's are diffeo/homeomorphic to compact rank one symmetric spaces.
Study verifies Homogeneity Conjecture for three odd-dimensional spheres in positive curvature.
problem Verifying the Homogeneity Conjecture for three specific odd-dimensional spheres in positive curvature.
method Developed methods to verify the conjecture for three odd-dimensional spheres.
result Completes verification of the Homogeneity Conjecture in positive curvature.
As was recently observed by M. Xu and J. Wolf, there is a gap in Berard Bergery's classification of odd dimensional positively curved homogeneous spaces. Since this classification has been used in other papers as well, we give a modern, complete and self contained proof (in odd as well as even dimensions), confirming t…
The known manifolds of positive sectional curvature are either homogeneous spaces or biquotients, i.e. quotients of a compact Lie group by a group acting on the left and right simultaneously. The full isometry group of the homogeneous metrics of positive curvature were determined by K.Shankar. Here we determine the iso…
Let G be a compact Lie group acting isometrically on a compact Riemannian manifold M with nonempty fixed point set MG. We say that M is fixed-point homogeneous if G acts transitively on a normal sphere to some component of MG. Fixed-point homogeneous manifolds with positive sectional curvature have been c…
A compact Riemannian homogeneous space G/H, with a bi--invariant orthogonal decomposition g=h+m is called positively curved for commuting pairs, if the sectional curvature vanishes for any tangent plane in TeH(G/H) spanned by a linearly independent commuting pair in $\mathfrak{…
New results affirmatively answer the stable converse soul question for many curved spaces.
problem Determining if vector bundles over curved spaces admit metrics with non-negative curvature.
method Topological K-theory and homotopy equivalence.
result The stable converse soul question has an affirmative answer for many curved spaces, except possibly for one specific space.
Formula derived for Laplace-Beltrami spectrum on homogeneous spaces.
problem Calculating the spectrum of the Laplace-Beltrami operator on homogeneous spaces.
method Formula derivation based on eigenvalues of a generalized Casimir operator and spherical representations.
result First detailed computation and investigation of the spectrum for a family of metrics on the Aloff-Wallach manifold.
No stable discrete maps into certain curved spaces exist.
problem Stability of discrete maps into curved spaces.
method Analysis of weighted length or energy functionals on graphs.
result Non-existence of stable discrete minimal immersions or harmonic maps into specific homogeneous spaces.
Study shows metrics on certain manifolds lose positive curvature under Ricci flow.
problem Understanding the dynamics of positively curved metrics on specific manifolds.
method Analysis of invariant metrics on SU(3)/T2 and SU(m+2p)/S(U(m)imesU(p)imesU(p)) under homogeneous Ricci flow. result Metrics lose positive intermediate Ricci curvature under Ricci flow for certain dimensions.
Generalizes SRVF to curves in homogeneous spaces for efficient distance computation.
problem Distance on curves in homogeneous spaces.
method Generalizes SRVF to homogeneous spaces and proves existence of optimal reparametrizations.
result Efficient computation of quotient distance on curves in homogeneous spaces.
This paper is devoted to the study of the evolution of positively curved metrics on the Wallach spaces SU(3)/Tmax, Sp(3)/Sp(1)×Sp(1)×Sp(1), and F4/Spin(8). We prove that for all Wallach spaces, the normalized Ricci flow evolves all generic invariant Riemannian metrics with positive sectional curv…
Let M be a hyperkähler manifold with b2(M)≥5. We improve our earlier results on the Morrison-Kawamata cone conjecture by showing that the Beauville-Bogomolov square of the primitive MBM classes (i.e. the classes whose orthogonal hyperplanes bound the Kähler cone in the positive cone, or, in other words, the cl…
This is a slightly altered version of the authors thesis from 2014. In the first main part we show that the quotient space of a compact, simply connected and nonnegatively curved Riemannian 4-manifold by an effective, isometric circle-action admits an approximation in Gromov-Hausdorff topology by smooth, positively cur…
We show how to specify preferred parameterisations on a homogeneous curve in an arbitrary homogeneous space. We apply these results to limit the natural parameters on distinguished curves in parabolic geometries.
The paper extends square root velocity framework to curves in homogeneous spaces.
problem Computing metrics and analyzing curves in homogeneous spaces.
method Generalized square root velocity framework to homogeneous spaces, identifying curves with horizontal lifts in G, computing geodesics, and performing quotient operations. result Geodesics and Karcher means can be computed in quotient spaces of curves in homogeneous spaces.
Enhances the Bishop-Gromov theorem for curved spaces, especially at late times.
problem The Bishop-Gromov theorem's volume growth upperbound is often too loose, especially at late times.
method Identified and quantified the effect of shear, using higher curvature invariants to improve the upperbound.
result Tighter upper bounds on late-time growth rates of geodesic balls in homogeneous spaces with non-positive sectional curvature.
Abstract: Characterizes spaces with positive scalar curvature.
problem Spaces with positive scalar curvature and invariant metrics.
method Cohomogeneity one manifolds and homogeneous spaces with compact Lie group actions.
result Characterization of spaces with positive scalar curvature.
Examples of almost-positively and quasi-positively curved spaces of the form M=H((G,h)xF) were discovered recently. Here, h is a left-invariant metric on a compact Lie group G, F is a compact Riemannian manifold on which the subgroup H of G acts isometrically on the left, and M is the orbit space of the diagonal left a…
Study distinguishes components of moduli spaces for certain metrics.
problem Distinguishing components of moduli spaces of metrics with nonnegative sectional curvature.
method Used Kreck-Stolz s invariant and formulas to calculate and distinguish components.
result Moduli spaces of metrics with nonnegative sectional curvature have infinitely many path components.
Characterizes equigeodesics on specific homogeneous spaces.
problem Understanding geodesics on homogeneous spaces.
method Analyzing curves on Stiefel manifolds, generalized Wallach spaces, and spheres.
result Characterizations of algebraic equigeodesics on specific spaces.
The current paper is devoted to the study of integral curves of constant type in parabolic homogeneous spaces. We construct a canonical moving frame bundle for such curves and give the criterium when it turns out to be a Cartan connection. Generalizations to parametrized curves, to higher-dimensional submanifolds and t…
New criterion for cylinder stability in curved spaces.
problem Stability of cylinders in curved spaces.
method Extending Plateau-Rayleigh criterion to curved spaces and proving existence of instability threshold.
result Existence of a positive number L0 for cylinder instability in E(κ,τ) spaces. The study preserves Ricci curvature positivity on homogeneous spaces under the normalized Ricci flow.
problem Preserving Ricci curvature positivity on homogeneous spaces under the normalized Ricci flow.
method Investigation of infinitely many generalized Wallach spaces (GWS) where Ricci curvature positivity is preserved.
result Infinite number of GWS where Ricci curvature positivity is preserved under the normalized Ricci flow.
Classifies manifolds with quasipositive curvature.
problem Classifying manifolds with quasipositive curvature.
method Generalized tools from positively curved cohomogeneity one manifolds.
result Classification of manifolds with quasipositive curvature.
Ricci flow on certain homogeneous spaces creates metrics with positive curvature.
problem Finding metrics with positive Ricci curvature on specific homogeneous spaces.
method Normalized Ricci flow on simply connected homogeneous spaces with two equivalent isotropy summands.
result Every G-invariant metric evolves to one with positive Ricci curvature under Ricci flow.
Study on triharmonic curves in 3D spaces, proving their existence and classification.
problem Characterizing triharmonic curves in 3D homogeneous spaces.
method Analyzing curves with constant curvature in Riemannian manifolds, focusing on Frenet helices and space forms.
result Classification of triharmonic Frenet helices in space forms and Bianchi-Cartan-Vranceanu spaces.
The Lp-cohomology in degree 1 of Riemannian homogeneous spaces is computed. It turns out that reduced cohomology does not vanish exactly for spaces quasiisometric to negatively curved homogeneous spaces.
Positive simplicial volume implies locally symmetric space structure.
problem Understanding simplicial volume in locally homogeneous spaces.
method Analyzing properties of locally homogeneous Riemannian manifolds.
result Closed locally homogeneous manifolds with positive simplicial volume are locally symmetric.
The paper extends Heintze-Kobayashi-Wolf theory to negatively curved homogeneous Finsler manifolds.
problem Understanding negatively curved homogeneous Finsler manifolds.
method Generalizing Heintze-Kobayashi-Wolf theory to homogeneous Finsler geometry, proving two main theorems.
result Negatively curved homogeneous Finsler manifolds are isometric to Lie groups with specific properties.
We prove local existence of complex-valued harmonic morphisms from any Riemannian homogeneous spaces of positive curvature, except the Berger space Sp(2)/SU(2).
Rollings of reductive homogeneous spaces are studied using intrinsic curves.
problem Investigate rollings of reductive homogeneous spaces without slip and twist.
method An intrinsic point of view, considering rollings as curves in the configuration space Q tangent to a certain distribution. result Explicit solutions for rollings of m over G/H are obtained for specific cases.