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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.

169,042 papers · 148 categories

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84167251334 · Jun 202019922001200920172026
48 results for center points

The k-means++ algorithm is generalized by choosing the most distant point from the nearest center.

problem Improving the initialization of k-means clustering.
method Generalizing the center initialization process by selecting the most distant point from the nearest center.
result Choosing the most distant point from the nearest center achieves similar clustering quality to k-means++.

We investigate centers of a body (the closure of a bounded open set) defined as maximum points of potentials. In particular, we study centers defined by the Riesz potential and by Poisson's integral. These centers, in general, depend on parameters and move with respect to the parameters. We give a necessary and suffici…

2016-03-28abs ↗pdf ↗

Private learner for halfspaces with efficient sample complexity.

problem Private learning of halfspaces over arbitrary domains.
method Differential privacy for center point location and its application to halfspace learning.
result Private halfspace learning with sample complexity poly(d,2logX)poly(d, 2^{\log^*|X|}).

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 ↗

A variant of the Circle Packing Theorem states that the combinatorial class of any convex polyhedron contains elements midscribed to the unit sphere centered at the origin, and that these representatives are unique up to Möbius transformations of the sphere. Motivated by this result, various papers investigate the prob…

2018-04-20abs ↗pdf ↗

We prove the existence of a center, or continuous selection of a point, in the relative interior of C1C^1 embedded kk-disks in Riemannian nn-manifolds. If k3k\le 3 the center can be made equivariant with respect to the isometries of the manifold, and under mild assumptions the same holds for k=4=nk=4=n. By contrast, for…

2017-06-25abs ↗pdf ↗

Models for 3D harmonic 1-forms and spinors near singular points.

problem Constructing models for Z/2\mathbb{Z}/2 harmonic 1-forms and spinors in 3D near singular points.
method Using symmetries of tetrahedron, octahedron, and icosahedron to construct local models on R3\mathbb{R}^3.
result Local models are Z/2\mathbb{Z}/2 harmonic 1-forms or spinors on R3\mathbb{R}^3 with zero locus consisting of rays from the origin.

Archimedes determined the center of gravity of a parabolic section as follows. For a parabolic section between a parabola and any chord ABAB on the parabola, let us denote by PP the point on the parabola where the tangent is parallel to ABAB and by VV the point where the line through PP parallel to the axis of the p…

2015-02-01abs ↗pdf ↗

Paper explores online k-means clustering, finding optimal bounds for center count.

problem Understanding the effects of online k-means clustering with unknown n.
method Analyzes different cases of online k-means clustering, proving optimal bounds.
result Optimal bounds for center count in various scenarios, showing Theta(log n) centers suffice.

Simplified proof of mass center system's uniqueness and generalized Pappus' theorem across Euclidean, spherical, and hyperbolic geometries.

problem Proving the uniqueness of the mass center system in non-Euclidean geometries and deriving a generalized Pappus' theorem.
method Revisiting and simplifying G.A. Galperin's proof, extending the mass center system to manifolds, and deriving a generalized Pappus' theorem.
result Unified and simpler proofs for Pappus' theorem in Euclidean, spherical, and hyperbolic geometries.

New clustering method ensures fairness and community preservation.

problem Fairness in clustering, especially for data points representing people.
method Developed an approach to extend kk-center algorithms to satisfy pairwise fairness and community preservation.
result Reasonable approximations of optimal clustering can be achieved while maintaining fairness.

We generalize the Riesz potential of a compact domain in Rm\mathbb{R}^{m} by introducing a renormalization of the rαmr^{α-m}-potential for α0α\le0. This can be considered as generalization of the dual mixed volumes of convex bodies as introduced by Lutwak. We then study the points where the extreme values of the (renorm…

2010-08-16abs ↗pdf ↗

Analyzes branch points of area-minimizing currents with non-2 planar frequency.

problem Understanding the structure of area-minimizing currents near branch points.
method Intrinsic frequency function and geometric arguments avoiding center manifolds.
result Establishes higher order asymptotics and topological control near branch points.

The purpose of this article is to \begin{enumerate} \item define M(t,k)M(t,k) the tt-fold center of mass arrangement for kk points in the plane, \item give elementary properties of M(t,k)M(t,k) and \item give consequences concerning the space M(2,k)M(2,k) of kk distinct points in the plane, no four of which are the vertices of …

2006-11-23abs ↗pdf ↗

Paper studies inscribed sphere and lines through centers of Apollonius spheres in n dimensions.

problem Tangency of spheres and lines through their centers.
method Lie sphere geometry and two-step construction of Apollonius spheres.
result Center of inscribed sphere coincides with point PXP_X.

We study the fixed point set in the ideal boundary of a parabolic isometry of a proper CAT(0)-space. We show that the radius of the fixed point set is at most pi/2, and study its centers. As a consequence, we prove that the set of fixed points is contractible with respect to the Tits topology.

2004-08-25abs ↗pdf ↗

The purpose of this article is to present a new regularization technique of quasi-plurisubharmoinc functions on a compact Kaehler manifold. The idea is to regularize the function on local coordinate balls first, and then glue each piece together. Therefore, all the higher order terms in the complex Hessian of this regu…

2017-05-20abs ↗pdf ↗

This paper constructs a family of coordinate systems about a point on a quaternionic contact manifold, called quaternionic contact pseudohermitian normal coordinates. Once defined, conformal variations of the quaternionic contact structure induce changes on the coordinates which are studied in an effort to simplify the…

2008-07-02abs ↗pdf ↗

CoCP optimizes prediction intervals by jointly learning center and radius, improving efficiency and coverage.

problem Inefficient conformal prediction intervals under heteroscedasticity and skewness.
method Co-optimization framework that learns center and radius through alternating optimization steps.
result CoCP yields consistently shorter intervals and state-of-the-art conditional coverage diagnostics.

Recently, Awasthi et al. introduced an SDP relaxation of the kk-means problem in Rm\mathbb R^m. In this work, we consider a random model for the data points in which kk balls of unit radius are deterministically distributed throughout Rm\mathbb R^m, and then in each ball, nn points are drawn according to a common ro…

2015-05-18abs ↗pdf ↗

We find that for any n-dimensional, compact, convex subset K of R^{n+1} there is an affinely-spherical hypersurface M in R^{n+1} with center at the relative interior of K, such that the disjoint union of M and K is the boundary of an (n+1)-dimensional, compact, convex set. This so-called affine hemisphere M is uniquely…

2015-08-03abs ↗pdf ↗

Refined estimates for surfaces in curved spaces based on Willmore functional.

problem Estimating the position of surfaces in curved spaces accurately.
method Critical points of the Willmore functional, constrained area, refined geometric center of mass.
result Improved position estimates related to ambient scalar curvature.