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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.

168,742 papers · 148 categories

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48 results for illumination body

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.

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.

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.

The object of our investigation is a point that gives the maximum value of a potential with a strictly decreasing radially symmetric kernel. It defines a center of a body in Rm. When we choose the Riesz kernel or the Poisson kernel as the kernel, such centers are called a radial center or an illuminating center, respec…

2016-03-09abs ↗pdf ↗

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.

Lie groupoids and their associated algebroids arise naturally in the study of the constitutive properties of continuous media. Thus, Continuum Mechanics and Differential Geometry illuminate each other in a mutual entanglement of theory and applications. Given any material property, such as the elastic energy or an inde…

2017-12-23abs ↗pdf ↗

We propose an automatic method to infer high dynamic range illumination from a single, limited field-of-view, low dynamic range photograph of an indoor scene. In contrast to previous work that relies on specialized image capture, user input, and/or simple scene models, we train an end-to-end deep neural network that di…

2017-04-01abs ↗pdf ↗

For a Veech surface (x,ω), we characterize subspaces of X^n, invariant under the diagonal action of the affine group of X. We prove that non-arithmetic Veech surfaces have only finitely many invariant subspaces of very particular shape (in any dimension). Among other consequences we find copies of (X,ω) embedded in the…

2006-02-17abs ↗pdf ↗

Enhances 2D face recognition with 3D features using active illumination.

problem Improving robustness of 2D face recognition to spoofing attacks and low-light conditions.
method Projecting a high spatial frequency pattern onto the face to recover 3D information and a 2D image simultaneously.
result Significantly boosts face recognition performance and dramatically improves robustness to spoofing attacks.

Visual perception is a challenging problem in part due to illumination variations. A possible solution is to first estimate an illumination invariant representation before using it for recognition. The object albedo and surface normals are examples of such representations. In this paper, we introduce a multilayer gener…

2012-06-27abs ↗pdf ↗

Automatic video modification to hide faces while maintaining pose, illumination, and expression.

problem Face de-identification in video to protect identities.
method A novel feed-forward encoder-decoder network architecture conditioned on facial image high-level representation.
result Fully automatic video modification at high frame rates with minimal distortion.

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.

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 ↗

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 ↗

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 ↗

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 Gauss curvature measure of a pointed Euclidean convex body is a measure on the unit sphere which extends the notion of Gauss curvature to non-smooth bodies. Alexandrov's problem consists in finding a convex body with given curvature measure. In Euclidean space, A.D. Alexandrov gave a necessary and sufficient condit…

2019-03-15abs ↗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 ↗

In this paper we use 3-manifold techniques to illuminate the structure of the category of tangles. In particular, we show that every idempotent morphism AA in such a category naturally splits as A=BCA=B\circ C such that CBC\circ B is an identity morphism.

2017-12-31abs ↗pdf ↗

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 ↗

New space of tensorial bodies defined, properties and representatives studied.

problem Characterizing convex bodies in tensor norms.
method Introduced a new space of tensorial bodies, defined a Banach-Mazur distance, and proved existence of a compact type compactum.
result Topological representatives for the space of tensorial bodies and the Banach-Mazur type compactum are given.

The paper proves convex bodies are minimal fillings and have Lipschitz-volume rigidity.

problem Finding minimal fillings of convex bodies.
method Analyzing integral current spaces and proving rigidity properties.
result Convex bodies are the unique minimal fillings of their boundary metrics among integral current spaces and enjoy Lipschitz-volume rigidity.

New periodic solutions found in 2n-body problem, braids of pseudo-Anosov type with stretch factors as metallic ratios.

problem Periodic solutions of the 2n-body problem and their braid types.
method Analyzing braid types and stretch factors associated with pseudo-Anosov braids.
result Braids from new periodic solutions are of pseudo-Anosov type with stretch factors as metallic ratios.

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.

We consider the class of λλ-concave bodies in Rn+1\mathbb R^{n+1}; that is, convex bodies with the property that each of their boundary points supports a tangent ball of radius 1/λ1/λ that lies locally (around the boundary point) inside the body. In this class we solve a reverse isoperimetric problem: we show that the co…

2018-09-29abs ↗pdf ↗

Analytic convex bodies' Poincaré series extended holomorphically.

problem Analytic continuation of Poincaré series for convex bodies.
method Analytic continuation of Laplace transforms, holomorphic functions, and resolvent of multiplication operators.
result Poincaré series continues holomorphically to a conical neighborhood of the right half-plane, removing countable cuts and points.