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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.

168,932 papers · 148 categories

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14284155 · May 202619922001200920172026
48 results for Geodesic hull

Sharp Poincaré inequality proved for specific metric spaces.

problem Proving a sharp Poincaré inequality for certain metric measure spaces.
method Identifying model densities and using localization arguments, without assuming geodesic convexity.
result Best possible Poincaré constant as a function of parameters.

The paper derives explicit geodesic equations for a specific type of group structure.

problem Finding geodesics in left-invariant sub-Finsler problems on Heisenberg groups.
method Using convex trigonometry and generalizations of spherical coordinates.
result Explicit formulae for geodesics in Heisenberg groups are derived.

Any two compact, complete, one-dimensional geodesic spaces with identical marked length spectrum have isometric π1π_1-hull. The present version contains errors, notably in Lemmas 2.2 and 2.3 (path cancellations can be more complicated), which then propagate through the paper. The main result is correct as stated, and a…

2003-01-26abs ↗pdf ↗

We consider non-elementary representations of two generator free groups in PSL(2,C)PSL(2,\mathbb{C}), not necessarily discrete or free, G=<A,B>G = < A, B >. A word in AA and BB, W(A,B)W(A,B), is a palindrome if it reads the same forwards and backwards. A word in a free group is {\sl primitive} if it is part of a minimal generating …

2008-08-26abs ↗pdf ↗

For every finite collection of curves on a surface, we define an associated (semi-)norm on the first homology group of the surface. The unit ball of the dual norm is the convex hull of its integer points. We give an interpretation of these points in terms of certain coorientations of the original collection of curves. …

2016-04-22abs ↗pdf ↗

We present a nonstandard hull construction for locally uniform groups in a spirit similar to Luxembourg's construction of the nonstandard hull of a uniform space. Our nonstandard hull is a local group rather than a global group. We investigate how this construction varies as one changes the family of pseudometrics used…

2012-03-29abs ↗pdf ↗

This paper defines maximal measurable cocycles for surface groups into Hermitian Lie groups and studies their algebraic hulls.

problem Understanding maximal measurable cocycles for surface groups into Hermitian Lie groups.
method Introducing the notion of maximal measurable cocycles, defining Toledo invariant, and studying the algebraic hulls.
result The algebraic hull of a maximal cocycle is reductive and its centralizer is compact.

Various results based on some convexity assumptions (involving the exponential map along with affine maps, geodesics and convex hulls) have been recently established on Hadamard manifolds. In this paper we prove that these conditions are mutually equivalent and they hold if and only if the Hadamard manifold is isometri…

2014-08-04abs ↗pdf ↗

Let SS be a compact, connected, oriented surface, possibly with boundary, of negative Euler characteristic. In this article we extend Lindenstrauss-Mirzakhani's and Hamenstädt's classification of locally finite mapping class group invariant ergodic measures on the space of measured laminations $\mathcal{M}\mathcal{L}(…

2018-07-05abs ↗pdf ↗

The n-th hull of a union of curves in R^3 is the set of points with the property: Any plane passing through the point intersects the curves at least 2n times. The hull number u(L) of a link L is defined as the minimum number of non-empty hulls a representative of L can have. We show that the hull numbers of torus links…

2004-12-07abs ↗pdf ↗

The main result of this paper is a characterization of the minimal surface hull of a compact set KK in R3\mathbb R^3 by sequences of conformal minimal discs whose boundaries converge to KK in the measure theoretic sense, and also by 22-dimensional minimal currents which are limits of Green currents supported by conf…

2014-09-24abs ↗pdf ↗

Develops harmonic metrics for Hull-Strominger system stability.

problem Existence of solutions to the Hull-Strominger system with balanced class.
method Uses non-Hermitian Yang-Mills connections and holomorphic Courant algebroids, introduces harmonic metrics.
result Expected existence of a numerical stability condition for generic families of solutions.

Study analyzes correlation structure in two-factor Hull-White model for XVA calculations.

problem Capturing the correlation structure in two-factor Hull-White model for accurate XVA calculations.
method Combination of approximation formula and Monte-Carlo simulation to investigate correlation structure.
result Hull-White model effectively captures de-correlation of the yield curve under specific parameter conditions.

Deep learning models generalize by extending decision boundaries outside the convex hull of training data.

problem Understanding how deep learning models generalize beyond their training data.
method Investigation of decision boundaries inside and outside the convex hull of training sets, using various neural network architectures and training regimes.
result Over-parameterization is necessary for deep learning models to extend decision boundaries outside the convex hull of their training data.

Let Wn\mathcal{W}^{n} be the class of CC^{\infty } complete simply connected nn-dimensional manifolds without conjugate points. The hyperbolic space as well as Euclidean space are good examples of such manifolds. Let % W\in \mathcal{W}^{n} and let AA be a subset of WW. This article aims at characterization and bu…

2013-11-03abs ↗pdf ↗

The integer hull of a polyhedron is the convex hull of the integer points contained in it. We show that the vertices of the integer hulls of a rational family of polyhedra of size O(n) have quasipolynomial coordinates. As a corollary, we show that the stable commutator length of elements in a surgery family is a ratio …

2010-11-05abs ↗pdf ↗

Study characterizes hulls and capacities on Riemannian manifolds, proving isoperimetric inequalities.

problem Characterizing hulls and capacities on Riemannian manifolds.
method Investigates strictly outward minimising hulls and uses p-capacities to recover their areas.
result Sharp isoperimetric inequality on complete noncompact manifolds with nonnegative Ricci curvature.

The convex hull of a set K in space consists of points which are, in a certain sense, "surrounded" by K. When K is a closed curve, we define its higher hulls, consisting of points which are "multiply surrounded" by the curve. Our main theorem shows that if a curve is knotted then it has a nonempty second hull. This pro…

2002-04-10abs ↗pdf ↗

New proofs given for space curves with totally positive torsion.

problem Description of convex hulls of space curves with totally positive torsion.
method New proofs of parametric representation, surface area, and volume formulas.
result Recovery of formulas for convex hull's surface area and volume.

We introduce the notion of a ``projective hull'' for subsets of complex projective varieties, parallel to the idea of the polynomial hull in affine varieties. With this concept, a generalization of J. Wermer's classical theorem on the hull of a curve in CnC^n is established in the projective setting. The projective hul…

2005-10-13abs ↗pdf ↗

Researchers link vertex algebras to non-Kähler solutions of the Hull-Strominger system.

problem Constructing representations of vertex algebras from non-Kähler solutions of the Hull-Strominger system.
method Embedding the N=2 superconformal vertex algebra in the chiral de Rham complex of a string Courant algebroid, with a condition on the Hermitian-Yang-Mills connection.
result Any solution of the Hull-Strominger system satisfying the Hermitian-Yang-Mills condition has an associated N=2 embedding.

Estimates convex hulls of smooth function images with error bounds.

problem Estimating the convex hull of the image of a smooth boundary set.
method Using submersion properties and sampling inputs, derive bounds on Hausdorff distance.
result New tighter and more general error bounds for geometric inference.

Study Hull-Strominger system and Anomaly flow on specific solvmanifolds.

problem Characterize invariant solutions to Hull-Strominger system and investigate flow of invariant metrics.
method Characterization of invariant solutions using Gauduchon connections, investigation of Anomaly flow, and proof of flow immortality under certain conditions.
result Anomaly flow reduces to a special form and always converges to a Kähler metric when slope parameter is zero.

Study convex hulls of orbits for compact groups, defining new invariants related to polynomial degrees.

problem Understanding properties of convex hulls of coadjoint orbits of compact groups.
method Introduce partial convex hulls and use them to define numerical invariants.
result Orbits with new invariants form rational convex polyhedral cones related to Littlewood-Richardson cones.

For a convex curve in an even-dimensional affine space we introduce a series of convex domains (called Young hulls), describe their structure and give a formulas fo the volume of the biggest of these domains. This paper is an attempt to generalize the classical isoperimetric inequality for the volume of the convex hull…

1996-11-18abs ↗pdf ↗

We obtain an upper bound for the volume of the convex hull of a simple closed Frenet curve with exactly four vertices, i.e., four points of vanishing torsion, and lying on the boundary of its convex hull. Moreover, we show that the upper bound is attained when the curve intersects every plane in at most four points, a …

2018-05-29abs ↗pdf ↗

New flow defined to solve Hull-Strominger system, with estimates and convergence results.

problem Constructing solutions to the Hull-Strominger system of equations.
method Introducing a natural extension of pluriclosed flow and using string algebroids and higher gauge theory.
result Proves global existence and convergence of the flow on special backgrounds.

Optimum in Convex Hulls (OCH) generalizes clinical trial results to broader populations.

problem Clinical trials exclude confounding but limit recruitment; observational data are more inclusive but suffer from confounding.
method OCH uses convex hulls of conditional expectations or densities to approximate the true treatment effect from both observational and trial data.
result OCH estimates the treatment effect with state-of-the-art accuracy in terms of both expectations and densities.

We obtain the following version of Lidskii theorem. Let L, M, N be p-dimensional subspaces in R^n. Let ψ_j be the angles between L and M, let φ_j be the angles between M and N, and let θ_j be the angles between L and N. Consider the orbit of the vector ψwith respect to permutations of coordinates and inversions of axis…

2000-05-06abs ↗pdf ↗

We show how to construct the nonstandard hull of certain infinite-dimensional Lie algebras in order to generalize a theorem of Pestov on the enlargeability of Banach-Lie algebras. In the process, we consider a nonstandard smoothness condition on functions between locally convex spaces to ensure that the induced functio…

2008-04-03abs ↗pdf ↗

Automorphisms and subdivisions of Helly graphs are studied, leading to explicit models and rational translation lengths.

problem Understanding automorphisms and subdivisions of Helly graphs.
method Simple fine simplicial subdivisions and explicit simplicial models of the injective hull.
result Any automorphism of a Helly graph is either elliptic or hyperbolic, with rational translation lengths.

We use twistor theory to identify the harmonic hull of an arbitrary connected open subset U of R^{2m} for m at least 2. It is the natural domain of analytic continuation in C^{2m} for harmonic functions on U.

2010-12-13abs ↗pdf ↗

GraphHull models networks with clear multi-scale explanations of community structure.

problem Lack of self-explainable models in graph machine learning.
method Two-level convex hulls with global archetypes and local prototypes.
result GraphHull models networks with clear multi-scale explanations.