Upper bound found for curvature of sphere actions.
problem Bounding the curvature of orbit spaces of sphere actions.
method Investigated isometric actions on unit spheres to find a universal upper bound.
result Found a universal upper bound for the infimum of curvatures of orbit spaces.
Rigidity of negatively curved geodesic orbit spaces proven.
problem Proving rigidity of geodesic orbit Finsler spaces with non-positive curvature.
method Analyzing strictly negative flag curvature and non-compact Riemannian symmetric spaces of rank one.
result A geodesic Finsler space with strictly negative flag curvature must be a non-compact Riemannian symmetric space of rank one.
Explicit bounds on orbit curvatures for Lie group actions.
problem Bounding orbit curvatures for Lie group actions.
method Explicit construction of orbits with bounded principal curvatures.
result Explicit bounds on orbit curvatures for unit spheres.
The paper extends geodesic orbit sphere classification to Finsler geometry.
problem Classifying geodesic orbit spheres in Finsler geometry.
method Generalized from Riemannian to Finsler geometry, proving constant curvature conditions.
result Geodesic orbit Finsler spheres with constant flag curvature are Randers.
Proves a quantitative closing lemma for negatively curved manifolds.
problem Closing lemma for negatively curved manifolds.
method Quantitative closing lemma proof.
result Study of partner and pseudo-partner orbits for self-crossing closed geodesics.
Study on orbit spaces with curvature bounds.
problem Understanding the curvature bounds of orbit spaces.
method Analyzing isometric actions on unit spheres.
result The infimum of sectional curvatures is 1 for most actions.
The paper studies mean curvature flows on specific orbits of Hermann actions.
problem Analyzing mean curvature flows on principal orbits of Hermann actions.
method Using Mathematica to illustrate and calculate the flows and orbits.
result The minimal principal orbit's position is calculated and illustrated.
We show that in cohomogeneity 3 there are G-manifolds with any given number of isolated singular orbits and an invariant metric of positive Ricci curvature. We show that the corresponding result is also true in cohomogeneity 5 provided the number of singular orbits is even.
We investigate the curvature of invariant metrics on G-manifolds with finitely many non-principal orbits. We prove existence results for metrics of positive Ricci curvature and non-negative sectional curvature, and discuss some families of examples to which these existence results apply.
Study sigma-models on flag manifolds with curvature zero and relate to chiral models.
problem Understanding sigma-models on flag manifolds with zero curvature.
method Use zero-curvature representation and nilpotent orbits theory.
result Established relation between flag manifold sigma-models and principal chiral models.
The paper studies curvatures and austere properties of orbits in symmetric spaces.
problem Analyzing curvatures and austere properties of orbits in symmetric spaces.
method Using Hermann actions and hyperpolar properties, the paper derives explicit formulas for principal curvatures and conditions for orbits to be austere.
result The paper provides conditions for orbits to be austere and extends previous results to a larger class of infinite-dimensional submanifolds.
Study on almost Kaehler geometry of Lie groups orbits.
problem Understanding the geometry of adjoint orbits of Lie groups.
method Explicit formulas for Chern-Ricci form, scalar curvature, and Nijenhuis tensor derived from root data.
result Explicit formulas and conditions for the Chern-Ricci form and Kaehler type quotients.
The study examines geodesic orbit Finsler spaces with non-negative flag curvature and (FP) condition, proving they are compact.
problem Characterizing geodesic orbit Finsler spaces with specific curvature conditions.
method Analyzes the interaction between geodesic orbit property and flag curvature conditions.
result Compactness of geodesic orbit Finsler spaces with non-negative flag curvature and (FP) condition.
Given a compact Riemannian manifold together with a group of isometries, we discuss MCF of the orbits and some applications: eg, finding minimal orbits. We then specialize to Lagrangian orbits in Kaehler manifolds. In particular, in the Kaehler-Einstein case we find a relation between MCF and moment maps which, for exa…
Study on G2 actions on symmetric spaces, focusing on orbit properties.
problem Investigating properties of orbits in symmetric spaces related to G2. method Classification and analysis of orbits as Riemannian submanifolds, focusing on principal curvatures and specific types of orbits.
result Classification and properties of orbits in symmetric spaces related to G2. Study geometric equations on cohomogeneity one manifolds near singular orbits.
problem Solving geometric equations like Ricci, Einstein, and soliton near singular orbits.
method Special assumption simplifies proof; general case solved in Part II.
result Existence and uniqueness of solutions near singular orbits.
Finite orbit of representations implies finite image for surface groups.
problem Understanding representations of surface groups with finite orbit under mapping class group action.
method Analyzing finite orbit properties of representations under mapping class group action.
result Representations with universally finite mapping class group orbit have finite image.
The paper classifies orbit closures of symplectic Lie algebras.
problem Classifying orbit closures of symplectic Lie algebras under the action of Sp(4,R). method Analyzing the natural action of Sp(4,R) on the set of 4-dimensional Lie algebras with symplectic structures. result A complete classification of orbit closures of 4-dimensional symplectic Lie algebras.
Study describes signatures of Ricci curvature on nilmanifolds.
problem Understanding Ricci curvature on nilpotent Lie groups.
method Link between Ricci endomorphism kernel and closed orbits in representation of GL group, proved using real GIT.
result Complete description of Ricci curvature signatures on nilmanifolds.
We investigate the submanifold geometry of the orbits of Hermann actions on Riemannian symmetric spaces. After proving that the curvature and shape operators of these orbits commute, we calculate the eigenvalues of the shape operators in terms of the restricted roots. As applications, we get a formula for the volumes o…
The paper studies metrics with constant scalar curvature on foliated manifolds.
problem Existence of metrics with constant scalar curvature on foliated manifolds.
method Analysis of orbit-like foliations and application of Kondrakov Embedding Theorem.
result Existence of metrics with constant scalar curvature on foliated manifolds.
Survey on collapsing manifolds using group actions and foliations.
problem Collapsing manifolds with controlled curvature.
method Using group actions and singular Riemannian foliations.
result Recent extensions to singular Riemannian foliations.
New technique shows non-orbifold singularities are undetectable by G-invariant spectrum.
problem Detecting non-orbifold singularities using the G-invariant spectrum.
method Generalized Sunada-Pesce-Sutton technique to the G-invariant setting.
result Found an isospectral pair of spaces, one orbifold and one with non-orbifold singularities.
In this paper, we investigate a curvature-adapted and proper complex equifocal submanifold in a symmetric space of non-compact type. The class of these submanifolds contains principal orbits of Hermann type actions as homogeneous examples. In future, the results in this paper will be used to give a submanifold geometri…
Paper studies how certain hypersurfaces collapse in Hilbert space.
problem Collapse of hypersurfaces in Hilbert space.
method Investigates mean curvature flow with specific conditions.
result Invariant hypersurfaces collapse to group orbits under flow.
Study counts and equidistributes geodesic orbits on curved spaces.
problem Counting and equidistribution of strongly reversible closed geodesics in negatively curved spaces.
method Generalized techniques from Sarnak and Erlandsson-Souto, thermodynamic formalism, and graphs of groups with 2-torsion.
result Asymptotic counting and equidistribution of geodesic orbits towards the Bowen-Margulis measure.
Study rigidifies Einstein manifolds with symmetry, proving conjecture.
problem Einstein manifolds with negative scalar curvature and Lie group action.
method Rigidity result for nilradical action and minimal Einstein submanifolds.
result Alekseevskii conjecture proven for negative scalar curvature homogeneous manifolds.
The paper studies magnetic curvature and proves the existence of closed orbits on low energy levels.
problem Existence of closed magnetic geodesics on low energy levels.
method Derived magnetic curvature operator and used Bonnet-Myers argument.
result Established the existence of a contractible periodic orbit on closed manifolds.
New electromagnetic curvature defined via Jacobi-Maupertuis, showing positive curvature for non-zero magnetic force.
problem Defining and analyzing electromagnetic curvature.
method Using Jacobi-Maupertuis reparametrization and energy analysis.
result Positive electromagnetic Ricci curvature for non-zero magnetic force and small potential.
The study proves curvature bounds for quotient spaces of isometric actions.
problem Proving curvature bounds for quotient spaces of isometric actions.
method Disintegrate absolutely continuous measures and define a functional to prove curvature bounds.
result Necessary and sufficient conditions for Ricci curvature to be bounded below.
Study uses regularized mean curvature flow on invariant hypersurfaces in Hilbert space.
problem Analyzing invariant hypersurfaces in Hilbert space.
method Regularized mean curvature flow with specific conditions.
result Invariant hypersurfaces collapse to group orbits under flow.
The paper studies Finsler spheres with constant flag curvature and finite orbits of prime closed geodesics.
problem Investigating Finsler spheres with specific curvature properties and geodesic orbits.
method Analyzing the action of isometries and loops on Finsler spheres, focusing on finite orbits of prime closed geodesics.
result The existence of geometrically distinct orbits of prime closed geodesics and their properties.
In this short note, we analyze geometric properties of orbit spaces of certain involutions in dimensions four, five, and six. We consider constructions of F-structures on manifolds of dimension at least four that allows us to study minimal entropy, minimal volume, collapse with bounded curvature, and sign o…
In this paper, we consider the motion of a particle on a surface of revolution under the influence of a central force field. We prove that there are at most two analytic central potentials for which all the bounded, nonsingular orbits are closed and that there are exactly two on some surfaces with constant Gaussian cur…
In this paper, we study the regularized mean curvature flow starting from invariant hypersurfaces in a Hilbert space equipped with an isometric almost free Hilbert Lie group action whose orbits are minimal regularizable submanifolds, where "almost free" means that the stabilizers of the group action are finite. First w…
We show how to lift positive Ricci and almost non-negative curvatures from an orbit space M/G to the corresponding G-manifold, M. We apply the results to get new examples of Riemannian manifolds that satisfy both curvature conditions simultaneously.
Unified treatment of eigenvalue processes using Riemannian geometry.
problem Eigenvalue processes in various settings.
method Riemannian submersion and gradient flow of isospectral orbits.
result Eigenvalue processes are projections of Brownian motion through Riemannian submersions.
The paper characterizes potential functions whose level sets are orbits in mechanical systems.
problem Characterizing smooth potential energy functions on the plane with specific level set properties.
method Analyzing inverse curvature flow and properties of level sets.
result Analytic or functions with totally path-disconnected critical sets must be radial, while every compact convex set is a critical set of a Levi potential.
Study on magnetic systems on surfaces with closed orbits.
problem Characterizing and proving rigidity of Zoll magnetic systems.
method Characterization and proof of rigidity for magnetic systems on surfaces of positive genus.
result Only magnetic systems with constant curvature metrics and functions yield Zoll Hamiltonian flows.
Defines rho numbers for metrics with positive scalar curvature.
problem Computing index classes for manifolds with boundary and cuspidal parabolics.
method Uses orbital integrals, delocalized eta invariants, and index theorems.
result Defines higher rho numbers for metrics with positive scalar curvature.
First we show that a curvature-adapted proper complex equifocal submanifold is a principal orbit of a Hermann type action under certain condition. Next we show that a proper complex equifocal submanifold is curvature-adapted under certain condition.
Smooth orbit equivalence proves metric equivalence for geodesic flows.
problem Proving metric equivalence for geodesic flows under orbit equivalence.
method Proving metric equivalence for geodesic flows under orbit equivalence.
result Smooth orbit equivalence implies conformal equivalence of metrics.
Study local topological constraints on Berry curvature in spin-orbit coupled Bose-Einstein condensates.
problem Understanding local topological obstructions to flattening Berry curvature in spin-orbit-coupled Bose-Einstein condensates.
method Adapting Pigazzini-Toda lower bound to Kaluza-Klein setting, analyzing harmonic part of torsion 3-form, and using exact pointwise curvature analysis.
result Obstruction kernel vanishes, preventing complete gauging-away of Berry phases even at zero net topological charge.
Let c be a periodic Reeb orbit on the boundary S of a compact star-shaped domain C in R4. We show that if there is an immersed symplectic disc f in C with boundary c then the self-linking number lk(c) of c equals 2 tan(f)-1 where tan(f) is the tangential self-intersection number of f. We also show that if C is convex a…
We consider the normalized Ricci flow evolving from an initial metric which is conformally compactifiable and asymptotically hyperbolic. We show that there is a unique evolving metric which remains in this class, and that the flow exists up to the time where the norm of the Riemann tensor diverges. Restricting to initi…
Examining orbits ending in binary collisions for three equal masses under an inverse cube force.
problem Analyzing orbits ending in binary collisions for three equal masses under an inverse cube force.
method Reparametrizing orbits as geodesics on a negatively curved metric on a pair of pants.
result Visibility properties of negatively curved surfaces describe orbits beginning or ending in binary collisions.
In this paper we address the following questions: (i) Let C⊂C2 be an orbit of a polynomial vector field which has finite total Gaussian curvature. Is C contained in an algebraic curve? (ii) What can be said of a polynomial vector field which has a finitely curved transcendent orbit? We give a positi…
We find the first examples of real hypersurfaces with two nonconstant principal curvatures in complex projective and hyperbolic planes, and we classify them. It turns out that each such hypersurface is foliated by equidistant Lagrangian flat surfaces with parallel mean curvature or, equivalently, by principal orbits of…