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A locally-built, LLM-digested index of recent arXiv papers in quant finance, geometry/topology, and statistical ML — keyword search served straight from SQLite on this machine.

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48 results for Star-shaped

New set-valued star-shaped risk measures introduced for better risk assessment.

problem Improving risk assessment in financial contexts.
method Developed new set-valued star-shaped risk measures and proved their representation theorems.
result Set-valued star-shaped risk measures can be represented as unions of set-valued convex risk measures.

Paper proves conjecture about star-shaped curves evolving under GAPF, but not always preserves star shape.

problem What conditions guarantee global existence of Gage's area-preserving flow for nonconvex initial curves?
method Using Dittberner's singularity analysis theory, constructed a ``flying wing'' curve to show limitations.
result Gage's area-preserving flow does not always preserve star-shapedness of evolving curves.

The paper studies dynamic star-shaped risk measures and their representation.

problem Representing dynamic star-shaped risk measures and their properties.
method Representation theorems for dynamic monetary and star-shaped risk measures.
result Dynamic star-shaped risk measures can be represented as the lower envelope of a family of dynamic convex risk measures.

The paper characterizes dynamic return and star-shaped risk measures via BSDEs.

problem Characterizing dynamic return and star-shaped risk measures.
method Characterization of star-shaped functionals and BSDEs.
result Existence of convex BSDEs with non-empty set of supersolutions.

The paper finds at least four prime closed characteristics on star-shaped hypersurfaces in 8D space.

problem Finding prime closed characteristics on compact star-shaped hypersurfaces in 8D space.
method Proved existence of at least four prime closed characteristics for non-degenerate C3C^3 compact star-shaped hypersurfaces in R8\mathbb{R}^{8} without prime closed characteristics of Maslov-type index -1.
result Existence of at least four prime closed characteristics on compact star-shaped hypersurfaces in R8\mathbb{R}^{8}.

The paper proves inequalities for star-shaped and FF-mean convex hypersurfaces in Rn+1\mathbb{R}^{n+1}.

problem Proving geometric inequalities for specific types of hypersurfaces.
method Using anisotropic pp-momentum, perimeter, and volume, the paper derives inequalities for star-shaped and FF-mean convex hypersurfaces.
result The Wulff shape of FF is the unique minimizer of the corresponding functionals among all star-shaped and FF-mean convex sets.

The paper characterizes law-invariant star-shaped risk measures.

problem Understanding and characterizing law-invariant star-shaped risk measures.
method Developed characterizations for positively homogeneous and star-shaped functionals, derived Kusuoka-type representations, and offered representations of general law-invariant star-shaped functionals.
result Characterizations of law-invariant star-shaped functionals, including their connections to Value-at-Risk and Expected Shortfall.

The paper generalizes convex and star-shaped concepts to symplectic spaces and studies variational problems.

problem Generalizing convex and star-shaped concepts to symplectic vector spaces.
method Study of variational problems for symplectically convex and star-shaped curves.
result Extremal points of the variational problem are rigid multiply traversed conics for a range of parameters.

In 1998 Smoczyk [Smo98] showed that, among others, the blowup limits at singularities are convex for the mean curvature flow starting from a closed star-shaped surface in R3\mathbf{R}^3. We prove in this paper that this is true for the mean curvature flow of star-shaped hypersurfaces in Rn+1\mathbf{R}^{n+1} in arbitrary …

2015-08-05abs ↗pdf ↗

This paper connects monetary and star-shaped risk measures by showing their equivalence under certain conditions.

problem Understanding the relationship between monetary and star-shaped risk measures.
method Analyzing the acceptability of 0 and the normalization property.
result Monetary risk measures are only a translation away from star-shapedness under mild conditions.

Proves a Minkowski inequality for star-shaped hypersurfaces in warped cylinders.

problem Proving a Minkowski inequality for specific types of hypersurfaces.
method Using weakly mean convex and star-shaped hypersurfaces in warped cylinders, and applying the inverse mean curvature flow.
result Sharp inequality holds for outward minimizing hypersurfaces in Schwarzschild and hyperbolic spaces.

Constructs Koszul dual algebras for star-shaped diagrams in 3-manifolds.

problem Constructing algebraic structures for 3-manifold homology.
method Uses graphical calculus to construct Koszul dual weighted A\mathcal{A}_{\infty}-algebras and dualizing bimodules.
result Proves duality of constructed algebras and bimodules.

Study eigenvalues for special curvature equations on star-shaped surfaces.

problem Eigenvalue problem for prescribed curvature equations on star-shaped, k-convex hypersurfaces.
method Established existence of a unique eigenvalue and hypersurface through uniform estimates in p for Lp-type equations.
result Existence of a unique eigenvalue and associated hypersurface under certain conditions.

Study of star-shaped hypersurfaces with capillary boundary using constrained mean curvature flow.

problem Understanding the evolution of hypersurfaces with capillary boundaries.
method Locally constrained mean curvature flow for star-shaped hypersurfaces in the half-space.
result Established new Alexandrov-Fenchel inequalities for convex hypersurfaces with capillary boundary.

Weakly convex polyhedra which are star-shaped with respect to one of their vertices are infinitesimally rigid. This is a partial answer to the question whether every decomposable weakly convex polyhedron is infinitesimally rigid. The proof uses a recent result of Izmestiev on the geometry of convex caps.

2007-04-22abs ↗pdf ↗

This work is an extension of a result given by Kuttler and Sigillito (SIAM Rev 1010:368370368-370, 19681968) on a star-shaped bounded domain in R2\mathbb{R}^2. Let ΩΩ be a star-shaped bounded domain in a hypersurface of revolution, having smooth boundary. In this article, we obtain a sharp lower bound for all Steklov eigenv…

2019-01-01abs ↗pdf ↗

We study the relation between the centro-affine geometry of star-shaped planar curves and the projective geometry of parametrized maps into $\RP^1$. We show that projectivization induces a map between differential invariants and a bi-Poisson map between Hamiltonian structures. We also show that a Hamiltonian evolution …

2008-08-26abs ↗pdf ↗

The paper proves new inequalities in hyperbolic space using Euclidean methods.

problem Proving weighted isoperimetric inequalities in hyperbolic space.
method Using isoperimetric inequality with log-convex density in Euclidean space.
result Removed horo-convex assumption and proved new inequalities for star-shaped domains.

The paper maps two types of hyperkähler manifolds and identifies their symplectic structures.

problem Mapping and identifying symplectic structures of two types of hyperkähler manifolds.
method Produced a map from star-shaped quiver varieties to Higgs bundle moduli spaces, verified stability, and showed it is a homeomorphism.
result Identified natural holomorphic symplectic structures on the two spaces.

In this paper we complete the study started in [Pi2] of evolution by inverse mean curvature flow of star-shaped hypersurface in non-compact rank one symmetric spaces. We consider the evolution by inverse mean curvature flow of a closed, mean convex and star-shaped hypersurface in the quaternionic hyperbolic space. We p…

2017-04-18abs ↗pdf ↗

We describe all families of star-shaped n-polygons in the Euclidean plane with prescribed perimeter and area ; they are leaves of a foliation F on the space of star-shaped n-polygons. By the way, we study some geometric properties of convex polygons, for instance their inscriptibility in a circle and their regularity i…

2019-02-12abs ↗pdf ↗

In this paper, we show that the inverse anisotropic mean curvature flow in Rn+1\mathbb{R}^{n+1}, initiating from a star-shaped, strictly FF-mean convex hypersurface, exists for all time and after rescaling the flow converges exponentially fast to a rescaled Wulff shape in the CC^\infty topology. As an application, we p…

2015-06-30abs ↗pdf ↗

The manifold M\mathcal{M} of star-shaped curves in Rn\mathbb{R}^n is considered via the theory of connections on vector bundles, and cyclic D\mathcal{D}-modules. The appropriate notion of an "integral curve" (i.e. certain admissible deformations) on M\mathcal{M} is defined, and the resulting space of admissible defo…

2018-11-01abs ↗pdf ↗

Proves local maximizers for higher Ekeland-Hofer capacities in 4D star-shaped domains.

problem Finding local maximizers for higher Ekeland-Hofer capacities in specific domains.
method Analogous to 4D local Viterbo conjecture, proving maximizers for rational ellipsoids.
result Local maximizers of the k-th Ekeland-Hofer capacities are symplectomorphic to rational ellipsoids.

Paper develops a new method for solving IBVPs on star-shaped domains.

problem Solving Inverse Boundary Value Problems (IBVP) for parallel transport equations.
method Covariant tomography, integrating geometric decomposition with specific interior extensions.
result Formal solvability criterion for higher-order IBVPs, validated through examples.

New algorithm for robust density estimation in corrupted data.

problem Density estimation in the presence of adversarial corruption.
method Proposes an algorithm for constructing a density estimator within a star-shaped density class, derived minimax bounds for estimation.
result Obtained minimax upper and lower bounds for density estimation under adversarial corruption.

We derive an upper bound on the waiting time for a variational weak solution to Inverse Mean Curvature Flow in Rn+1\mathbb{R}^{n+1} to become star-shaped. As a consequence, we demonstrate that any connected surface moving by the flow which is not initially a topological sphere develops a singularity or self-intersection …

2019-09-03abs ↗pdf ↗

We consider the evolution by inverse mean curvature flow of a closed, mean convex and star-shaped hypersurface in the complex hyperbolic space. We prove that the flow is defined for any positive time, the evolving hypersurface stays star-shaped and mean convex. Moreover the induced metric converges, after rescaling, to…

2016-10-06abs ↗pdf ↗

Paper proves Koszul duality for weighted A-infinity algebras.

problem Koszul duality for weighted A-infinity algebras.
method Constructs new box tensor product for weighted A-infinity bimodules and verifies correspondence between maps and bimodules.
result Proves Koszul duality result between weighted A-infinity algebras.

We consider a compact, star-shaped, mean convex hypersurface Σ2R3Σ^2\subset \mathbb{R}^3. We prove that in some cases the flow exists until it shrinks to a point in a spherical manner, which is very typical for convex surfaces as well (see \cite{An1}). We also prove that in the case we have a surface of revolution which …

2008-06-10abs ↗pdf ↗

The study shows infinitely many Reeb orbits on star-shaped hypersurfaces with growth rate like prime numbers.

problem Growth rate of Reeb orbits on star-shaped hypersurfaces.
method Analyzing fiberwise star-shaped hypersurfaces in cotangent bundles with topological conditions.
result The number of Reeb orbits with period at most T grows at least like T/log(T).

The study proves the existence of kk-convex hypersurfaces for specific curvature equations.

problem Proving the existence of kk-convex hypersurfaces for Hessian curvature equations.
method Combining a priori estimates with the continuity method, and establishing a constant rank theorem.
result Existence and uniqueness of kk-convex hypersurfaces for both nonhomogeneous and homogeneous Hessian curvature equations.

Let ΩΩ be a star-shaped bounded domain in (Sn,ds2)(\mathbb{S}^{n}, ds^{2}) with smooth boundary. In this article, we give a sharp lower bound for the first non-zero eigenvalue of the Steklov eigenvalue problem in Ω.Ω. This result is the generalization of a result given by Kuttler and Sigillito for a star-shaped bounded doma…

2018-02-11abs ↗pdf ↗

The study examines evolving star-shaped hypersurfaces in hyperbolic spaces, influenced by ambient geometry.

problem Evolution of star-shaped hypersurfaces in hyperbolic spaces.
method Nonhomogeneous expanding curvature flows in hyperbolic spaces.
result The asymptotic behavior of the flow depends on the ambient space's geometry, leading to different limiting metrics.