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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.

168,695 papers · 148 categories

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48 results for ball

This paper describes a method to construct standard 4-balls from homotopy 4-balls in C2\mathbb{C}^2.

problem The problem is whether every homotopy 4-ball in S4S^4 is standard.
method The approach is to use Stein surfaces and pseudoconvex domains to construct a diffeomorphic domain that is the union of three pseudoconvex domains, ensuring it is a standard 4-ball.
result The construction method ensures that the domain is a standard 4-ball, providing a compelling reimbedding construction for homotopy 4-balls in C2\mathbb{C}^2.

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.

New examples show non-locally-flat PL-disk bounds in rational homology balls but not in integer homology balls.

problem Characterizing knots that bound PL-disks in integer homology balls.
method Involutive Heegaard Floer homology formal properties.
result Found infinitely many manifold-knot pairs (Y, J) where J does not bound a PL-disk in an integer homology ball but does in a rational homology ball.

Study shows no smooth embeddings of rational homology balls into complex projective plane.

problem Embedding rational homology balls into complex projective plane.
method Elementary arguments to prove non-existence of almost complex embeddings.
result No smooth embeddings of rational homology balls into complex projective plane.

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.

In hyperbolic space HnH^n we set a geodesic ball of radius ρρ. Consider a kk dimensional minimal submanifold passing through the origin of the geodesic ball with boundary lies on the boundary of that geodesic ball. We prove that its area is no less than the totally geodesic kk dimensional submanifold passing through…

2016-12-08abs ↗pdf ↗

The paper characterizes unit balls among Stein spaces with specific groups using Bergman-Einstein metrics.

problem Characterizing unit balls among Stein spaces with specific groups.
method Study of Bergman metric on finite ball quotients and its Kähler-Einstein property.
result The Bergman-Einstein metric exists only on the unit ball itself for finite ball quotients with trivial groups.

Fintushel and Stern showed that the Brieskorn sphere Σ(2,3,7)Σ(2,3,7) bounds a rational homology ball, while its non-trivial Rokhlin invariant obstructs it from bounding an integral homology ball. It is known that their argument can be modified to show that the figure-eight knot is rationally slice, and we use this fact to p…

2017-04-25abs ↗pdf ↗

Study compares eigenvalues on spherically symmetric manifolds to Euclidean balls.

problem Comparing eigenvalues on spherically symmetric manifolds to Euclidean balls.
method Examines Dirichlet Laplace eigenvalues on balls of spherically symmetric manifolds and Euclidean space.
result Eigenvalues on spherically symmetric manifolds are smaller for small radii, but larger for hyperbolic spaces.

We prove the diameter of the intersection of two closed convex balls in a Riemannian manifold eventually decreases continuously as the centers of the balls move apart.

2019-05-17abs ↗pdf ↗

We describe two methods for showing that a vector can not be the f-vector of a homology d-ball. As a consequence, we disprove a conjectured characterization of the f-vectors of balls of dimension five and higher due to Billera and Lee. We also provide a construction of triangulated balls with various f-vectors. We show…

2009-12-10abs ↗pdf ↗

The paper constructs new rational homology 3-spheres bounding rational homology 4-balls.

problem Constructing rational homology 3-spheres that bound rational homology 4-balls.
method Exploring plumbed 3-manifolds and using rational homology circles.
result Infinite families of rational homology 3-spheres that bound rational homology 4-balls.

The Farey tree helps embed rational balls and lens spaces into complex projective space.

problem Embedding rational homology balls and lens spaces into complex projective space.
method Recursive Kirby calculus argument using the Farey tree.
result Explicit constructions of embeddings of triples of rational homology balls into homotopy CP2\mathbb{CP}^2.

Study free boundary minimal submanifolds in geodesic balls in hyperbolic and spherical spaces.

problem Characterize free boundary minimal submanifolds in geodesic balls of hyperbolic and spherical spaces.
method Define and analyze functionals related to critical metrics and spectral indices.
result Critical metrics of defined functionals arise from free boundary minimal immersions in geodesic balls of hyperbolic and spherical spaces.

Geodesic balls with non-negative Ricci curvature have a sharp lower bound on their first Dirichlet eigenvalue.

problem Finding a sharp lower bound for the first Dirichlet eigenvalue of geodesic balls.
method Quantitative explicit inequality linking the width of geodesic balls to the spectral gap.
result A quantitative inequality relating the width of geodesic balls to the spectral gap between the first Dirichlet eigenvalue and its lower bound.

This paper classifies ball quotients of the complex projective plane.

problem Understanding the structure of the complex projective plane as a ball quotient.
method Analyzing the branch locus as a line arrangement and smooth normal-crossing curves.
result The orbifold structure of (P2,D)(\mathbb{P}^2,D) is isomorphic to either the Deligne-Mostow example or a certain degree 9 cover.

A well-known and interesting family of sub-Riemannian space are the systems involving two balls rolling against each other without slipping or twisting. In this note, we show how the sub-Riemannian geodesics of these space, when the two balls are embedded in R3×R3\mathbb{R}^3 \times \mathbb{R}^3, are horizontal curves on …

2012-08-28abs ↗pdf ↗

The small-ball method was introduced as a way of obtaining a high probability, isomorphic lower bound on the quadratic empirical process, under weak assumptions on the indexing class. The key assumption was that class members satisfy a uniform small-ball estimate: that Pr(fκfL2)δPr(|f| \geq κ\|f\|_{L_2}) \geq δ for given const…

2017-09-04abs ↗pdf ↗

Investigate pseudoconvexity of locally trivial holomorphic ball bundles over compact Riemann surfaces.

problem Pseudoconvexity of locally trivial holomorphic ball bundles over compact Riemann surfaces.
method Prove that any such bundle is 1-convex, while its complement is n-convex.
result Prove that any such bundle is 1-convex, while its complement is n-convex.

We prove global estimates for the sub-Riemannian distance of CR Sasakian manifolds with non negative horizontal Webster-Tanaka Ricci curvature. In particular, in this setting, large sub-Riemannian balls are comparable to Riemannian balls.

2011-10-05abs ↗pdf ↗

We study the number of distinct ways in which a smooth projective surface XX can be realized as a smooth toroidal compactification of a ball quotient. It follows from work of Hirzebruch that there are infinitely many distinct ball quotients with birational smooth toroidal compactifications. We take this to its natural…

2015-03-23abs ↗pdf ↗

Ball k-means reduces point-centroid distance computations for faster k-means clustering.

problem Efficiently finding k-means clusters in large datasets.
method Uses a ball to describe clusters, dividing them into stable and active areas, and adjusting points within annulus areas.
result Significantly reduces point-centroid distance computations, making k-means faster and more efficient.