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arXiv research

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.

168,738 papers · 148 categories

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9182635 · May 202619922001200920172026
48 results for spherical bodies

For a convex body on the Euclidean unit sphere the spherical convex floating body is introduced. The asymptotic behavior of the volume difference of a spherical convex body and its spherical floating body is investigated. This gives rise to a new spherical area measure, the floating area. Remarkably, this floating area…

2014-11-27abs ↗pdf ↗

Study spherical convex bodies using LpL_p-floating areas and curvature entropy.

problem Analogous isoperimetric inequalities for spherical convex bodies.
method Introduced LpL_p-floating areas and curvature entropy for spherical convex bodies.
result Established isoperimetric inequalities and dual isoperimetric inequalities.

Study on spherical bodies of constant width on the unit sphere, proving bounds on their relative effective radius.

problem Understanding the smallest spherical bodies of constant width on the unit sphere.
method Analyzing spherical bodies of constant width on the unit sphere, constructing examples and applying geometric arguments.
result Proved non-trivial bounds on the relative effective radius of spherical bodies of constant width.

We investigate weighted floating bodies of polytopes. We show that the weighted volume depends on the complete flags of the polytope. This connection is obtained by introducing flag simplices, which translate between the metric and combinatorial structure. Our results are applied in spherical and hyperbolic space. This…

2018-05-29abs ↗pdf ↗

The paper explores centroids and static equilibrium points in non-Euclidean geometries.

problem Investigating centroids and static equilibrium points in spherical, hyperbolic, and normed spaces.
method Extending Gal'perin's work, the paper examines convex bodies in these spaces and analyzes the minimum number of equilibrium points.
result Every plane convex body in any of these spaces has at least four equilibrium points, and there are mono-monostatic convex bodies in 3D spherical, hyperbolic, and certain normed spaces.

Study on curvature measures in non-Euclidean spaces linked to Euclidean geometry.

problem Investigating curvature measures in spherical, hyperbolic, and de Sitter spaces.
method Establishing a unifying framework for curvature measures in real-analytic spaces of constant curvature.
result Floating bodies and duality in non-Euclidean spaces are connected to curvature measures in Euclidean space.

The spherical Radon transform on the unit sphere can be regarded as a member of the analytic family of suitably normalized generalized cosine transforms. We derive new formulas for these transforms and apply them to study classes of intersections bodies in convex geometry.

2006-02-24abs ↗pdf ↗

Rotation intertwining maps from the set of convex bodies in Rn into itself that are continuous linear operators with respect to Minkowski and Blaschke addition are investigated. The main focus is on Blaschke-Minkowski homomorphisms. We show that such maps are represented by a spherical convolution operator. An applicat…

2012-07-31abs ↗pdf ↗

Fixed points of mean section operators found in convex bodies.

problem Characterizing fixed points of mean section operators in convex bodies.
method Characterization of rotation equivariant operators using spherical Laplacian mass distribution, and application of Minkowski valuations.
result Euclidean balls are the only fixed points of mean section operators in a C2C^2 neighborhood of the unit ball.

A Minkowski class is a closed subset of the space of convex bodies in Euclidean space Rn which is closed under Minkowski addition and non-negative dilatations. A convex body in Rn is universal if the expansion of its support function in spherical harmonics contains non-zero harmonics of all orders. If K is universal, t…

2012-07-31abs ↗pdf ↗

Study the Hessian geometry of an ideal gas in a centrifuge.

problem Understanding the Hessian geometry of an ideal gas in a centrifuge.
method Investigate the Hessian geometry associated with an ideal gas in a spherical centrifuge, using the action of the Euclidean rotation group.
result The Hessian geometry of a spherical rigid body is isometric to a hyperbolic space in the high angular velocity limit.

Can the Minkowski sum of two compact convex bodies be made smoother by rotating one of them? We construct two infinitely differentiable strictly convex plane bodies such that after any generic rotation (in the Baire category sense) of one of the summands the Minkowski sum is not five times differentiable. On the other …

2016-07-10abs ↗pdf ↗

Louis Poinsot has shown in 1854 that the motion of a rigid body, with one of its points fixed, can be described as the rolling without slipping of one cone, the 'body cone', along another, the 'space cone', with their common vertex at the fixed point. This description has been further refined by the second author in 19…

2019-08-14abs ↗pdf ↗

The dual Minkowski problem for even data asks what are the necessary and sufficient conditions on an even prescribed measure on the unit sphere for it to be the qq-th dual curvature measure of an origin-symmetric convex body in Rn\mathbb{R}^n. A full solution to this is given when 1<q<n1 < q < n. The necessary and suffic…

2017-03-18abs ↗pdf ↗

Solves Christoffel-Minkowski problem and Hessian equations with radial symmetry.

problem Christoffel-Minkowski problem and Hessian equations under rotational symmetries.
method Constructing explicit convex solutions to mixed Monge-Ampère equations on \(\mathbb{R}^n\) under radial symmetry.
result Explicit representation formula for the support function of the resulting convex body.

Compact proof for Brown-York mass positivity and rigidity in flat and spherical spaces.

problem Positivity of Brown-York mass and rigidity of manifolds with mean-convex boundaries.
method Spinorial proof and optimal lower bound for eigenvalues.
result Optimal lower bound for first non-null eigenvalue of Dirac operator.

We study the stability of capillary hypersurfaces in a unit Euclidean ball. It is proved that if the mass center of the generalized body enclosed by the immersed capillary hypersurface and the wetted part of the sphere is located at the origin, then the hypersurface is unstable. An immediate result is that all known ex…

2014-08-09abs ↗pdf ↗

In this paper we analyze the capacitary potential due to a charged body in order to deduce sharp analytic and geometric inequalities, whose equality cases are saturated by domains with spherical symmetry. In particular, for a regular bounded domain ΩRnΩ\subset \mathbb{R}^n, n3n\geq 3, we prove that if the mean curvature…

2017-05-28abs ↗pdf ↗

The paper solves a specific Minkowski problem for capillary hypersurfaces.

problem Finding capillary convex bodies with prescribed dual curvature measures.
method Reduction to a Monge-Ampère type equation with Robin boundary condition.
result Existence and uniqueness of a smooth solution for θ(0,π2)θ\in (0,\fracπ{2}).

We show that the complex projective space has maximal degree (volume) among all n-dimensional Kahler-Einstein Fano manifolds admitting a holomorphic C^*-action with a finite number of fixed points. The toric version of this result, translated to the realm of convex geometry, thus confirms Ehrhart's volume conjecture fo…

2012-04-05abs ↗pdf ↗

New illumination bodies defined for ball-convex shapes, proving convexity and establishing surface area measures.

problem Characterizing properties of ball-convex shapes.
method Introducing illumination bodies and weighted illumination bodies, proving convexity, and establishing surface area measures.
result Illumination bodies are convex and provide surface area measures for ball-convex shapes.

New surface area measures defined for ball-convex bodies, leading to entropy and inequalities.

problem Defining and analyzing surface area measures for ball-convex bodies.
method Introducing LpL_p relative surface areas, proving invariance and inequalities, and using geometric interpretations.
result Established inequalities and a new notion of entropy for ball-convex bodies.

A groupoid Ω(B)Ω\left( \mathcal{B} \right) called material groupoid is naturally associated to any simple body B\mathcal{B}. The material distribution is introduced due to the (possible) lack of differentiability of the material groupoid. Thus, the inclusion of these new objects in the theory of material bodies opens th…

2018-12-11abs ↗pdf ↗

The paper finds the unique minimizer of area for hyperbolic bodies with curvature constraints.

problem Finding the unique minimizer of area for hyperbolic bodies with curvature constraints.
method Introduced the concept of 'thick λλ-sausage' bodies and used extra assumption of thickness to handle non-convex inner parallel bodies.
result The thick λλ-sausage body is the unique minimizer of area among all bodies with a given length and curvature constraints.

Extends illumination bodies to non-Euclidean spaces and proves their volume derivative defines surface area.

problem Defining surface area in non-Euclidean geometries.
method Generalizes illumination bodies to Riemannian spaces of constant curvature and projective Finsler geometries, proving their volume derivative defines surface area.
result Derivative of volume of illumination bodies defines surface area in non-Euclidean geometries.

We introduce and study a new class of $\eps$-convex bodies (extending the class of convex bodies) in metric and normed linear spaces. We analyze relations between characteristic properties of convex bodies, demonstrate how $\eps$-convex bodies connect with some classical results of Convex Geometry, as Helly theorem, an…

2008-08-13abs ↗pdf ↗

Analogues of the classical inequalities from the Brunn-Minkowski theory for rotation intertwining additive maps of convex bodies are developed. Analogues are also proved of inequalities from the dual Brunn-Minkowski theory for intertwining additive maps of star bodies. These inequalities provide generalizations of resu…

2012-07-31abs ↗pdf ↗

We consider the motion of small bodies in general relativity. The key result captures a sense in which such bodies follow timelike geodesics (or, in the case of charged bodies, Lorentz-force curves). This result clarifies the relationship between approaches that model such bodies as distributions supported on a curve, …

2017-07-13abs ↗pdf ↗

Prove a generalization of Werner's formula for the volume of illumination bodies on Riemannian manifolds.

problem Prove a generalization of Werner's formula for the volume of illumination bodies on Riemannian manifolds.
method Define the δδ-illumination body and prove a generalization of Werner's formula.
result Prove a generalization of Werner's formula for the volume of illumination bodies on Riemannian manifolds.

This paper is dedicated to the Orlicz-Petty bodies. We first propose the homogeneous Orlicz affine and geominimal surface areas, and establish their basic properties such as homogeneity, affine invariance and affine isoperimetric inequalities. We also prove that the homogeneous geominimal surface areas are continuous, …

2016-11-14abs ↗pdf ↗

When SS is a closed, orientable surface with genus g(S)2g(S) \geq 2, we show that the automorphism group of the compression body graph CB(S)\mathcal{CB}(S) is the mapping class group. Here, vertices are compression bodies with exterior boundary SS, and edges connect pairs of compression bodies where one contains the other.

2015-08-12abs ↗pdf ↗