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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.

168,694 papers · 148 categories

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163327490653 · Jun 202019922001200920172026
48 results for isotropic functions

The paper classifies critical metrics on manifolds with positive isotropic curvature.

problem Classifying critical metrics on manifolds with positive isotropic curvature.
method Analyzing the volume functional and solving a differential equation.
result Critical metrics are isometric to geodesic balls in S^n or specific products when conditions are met.

This work extends holomorphic surface representations to isotropic space.

problem Representing minimal surfaces in simply isotropic space with degenerate metrics.
method Developed new forms of Weierstrass and Björling representations for isotropic minimal surfaces.
result Holomorphic representations of isotropic minimal surfaces are achieved.

Develops a nonparametric method to estimate isotropic covariance functions efficiently.

problem Estimating isotropic covariance functions without assuming a specific parametric form.
method Uses Bernstein polynomials and sieve maximum likelihood estimation.
result Consistent estimator with improved performance compared to parametric and nonparametric alternatives.

The study of Laguerre isotropic hypersurfaces with rigidity and isoparametric properties.

problem Characterizing and understanding Laguerre isotropic hypersurfaces.
method Analyzing hypersurfaces with zero Laguerre form and constant eigenvalues of the Laguerre tensor.
result For L-isotropic hypersurfaces, if they are also L-isoparametric, the constant λλ must be zero.

We study singularities of geodesics flows in two-dimensional generalized Finsler spaces (pseudo-Finsler spaces). Geodesics are defined as extremals of a certain auxiliary functional whose non-isotropic extremals coincide with extremals of the action functional. This allows to consider isotropic lines as (unparametrized…

2015-07-23abs ↗pdf ↗

We prove ultradifferentiable Chevelley restriction theorems for a wide range of ultradifferentiable classes. As a special case we find that isotropic functions, i.e., functions defined on the vector space of real symmetric matrices invariant under the action of the special orthogonal group by conjugation, possess some …

2019-12-19abs ↗pdf ↗

Paper proves conjecture about Einstein metrics on manifolds with positive isotropic curvature.

problem Proving the Besse conjecture for metrics with positive isotropic curvature.
method Analyzing the critical point equation and using properties of metrics with positive isotropic curvature.
result The Besse conjecture is true for metrics with positive isotropic curvature.

Study isotropic solutions in smooth metric measure spaces with vacuum Einstein equations.

problem Investigate isotropic solutions in smooth metric measure spaces under vacuum Einstein field equations.
method Define a weighted Einstein tensor and associated vacuum field equations. Analyze solutions for different spacetime types.
result Isotropic solutions have nilpotent Ricci operator and specific forms in 2- and 3-step nilpotent manifolds.

We investigate the local structure of four-dimensional Lorentzian quasi-Einstein manifolds under conditions on the Weyl tensor. We show that if the Weyl tensor is harmonic and the potential function preserves this harmonicity then, in the isotropic case, the manifold is necessarily a pppp-wave. Using the quasi-Einstein…

2019-05-09abs ↗pdf ↗

The paper examines Randers metrics with isotropic scalar curvature properties.

problem Characterizing Randers metrics with specific scalar curvature properties.
method Analyzes properties of Randers metrics with isotropic scalar curvature.
result Proves that Randers metrics with weakly isotropic scalar curvature have isotropic SS-curvature and are either Minkowskian or Riemannian.

In this paper, we address the problem of determining a function in terms of its orbital integrals on Lorentzian symmetric spaces. It has been solved by S. Helgason for even-dimensional isotropic Lorentzian symmetric spaces via a limit formula involving the Laplace-Beltrami operator. The result has been extended by J. O…

2018-04-23abs ↗pdf ↗

Study physical work done by isotropic vector forces along isotropic curves.

problem Investigate physical work done by isotropic vector forces.
method Analyze forces represented by isotropic vectors acting along isotropic curves on a manifold with specific metric structures.
result Calculate the work done by isotropic vector forces along isotropic curves.

SGD learns neural networks with a complexity measure called leap.

problem Time complexity of SGD learning on neural networks.
method Introduced a complexity measure called leap, proved conjecture for Gaussian data, and showed saddle-to-saddle dynamics.
result Proved a conjecture about the time complexity of learning functions with low-dimensional support.

In this paper, we construct a new class of Finsler manifolds called generalized isotropic Berwald manifolds which is an extension of the class of isotropic Berwald manifolds. We prove that every generalized isotropic Berwald manifold is a generalized Douglas-Weyl manifold. On a compact generalized isotropic Berwald man…

2013-02-12abs ↗pdf ↗

Spinor representation in isotropic space via Laguerre geometry.

problem Representing conformal and constant mean curvature surfaces in isotropic space.
method Developing Laguerre geometry of isotropic space, defining spin transformations, and constructing Weierstrass and Kenmotsu representations.
result Explicit constructions of zero mean curvature and constant mean curvature surfaces.

The paper studies hanging chains and surfaces in degenerate geometries.

problem Investigating hanging chains and surfaces in simply isotropic plane and space.
method Characterizing catenaries and proving them as minimal surfaces in the simply isotropic space.
result The simply isotropic catenary is the generating curve of a minimal surface of revolution.

In this paper we will show that a Lagrangian, Lorentzian surface M12M^2_1 in a complex pseudo space form M~12(4c)\widetilde M^2_1 (4c) is pseudo-isotropic if and only if MM is minimal. Next we will obtain a complete classification of all Lagrangian, Lorentzian surfaces which are lightlike pseudo-isotropic but not pseudo-isot…

2016-10-05abs ↗pdf ↗

We show that for m>n2m>n\geq 2, there are at least two exact isotropic nn-tori in Cm\mathbb{C}^m which are not Hamiltonian isotopic in Cm\mathbb{C}^m, even though they are smoothly isotopic as isotropic nn-tori. We apply this discovery to obtain more distinct non-exact isotropic tori in Cm\mathbb{C}^m.

2016-03-30abs ↗pdf ↗

Study classifies zero mean curvature surfaces with planar curvature lines.

problem Characterizing surfaces with specific curvature properties.
method Complete classification and investigation of their relationship to Thomsen-type surfaces.
result Zero mean curvature surfaces with planar curvature lines belong to a 1-parameter family.

This paper aims to provide a description of totally isotropic Willmore two-spheres and their adjoint transforms. We first recall the isotropic harmonic maps which are introduced by Hélein, Xia-Shen and Ma for the study of Willmore surfaces. Then we derive a description of the normalized potential (some Lie algebra valu…

2016-04-10abs ↗pdf ↗

Paper improves learning efficiency by focusing on effective dimensionality.

problem Dimensionality bottleneck in modern learning tasks.
method Developed tools to reduce dimensional costs using effective dimensionality.
result Uniform concentration bounds involving effective dimensionality, improving over existing results.

Study surfaces with constant ratio of principal curvatures in Euclidean and isotropic geometries.

problem Characterize surfaces with constant ratio of principal curvatures in different geometries.
method Differential geometry, line geometry, Lie sphere geometry, ordinary differential equations, algebraic geometry.
result Characterized various types of surfaces like rotational, channel, ruled, helical, and translational.

The study finds compact vacuum static spaces with positive isotropic curvature are spheres or products of a circle and sphere.

problem Characterizing compact vacuum static spaces with positive isotropic curvature.
method Proving isometric equivalence to spheres or product spaces.
result Compact vacuum static spaces with positive isotropic curvature are isometric to spheres or product spaces.

Let Rn+1,nR^{n+1, n} be the vector space R2n+1R^{2n+1} equipped with the bilinear form (X,Y)=XtCnY(X,Y)=X^t C_n Y of index nn, where Cn=i=12n+1(1)n+i1ei,2n+2iC_n= \sum_{i=1}^{2n+1} (-1)^{n+i-1} e_{i, 2n+2-i}. A smooth γ:RRn+1,nγ: R\to R^{n+1,n} is {\it isotropic} if γ,γx,,γx(2n)γ, γ_x, \ldots, γ_x^{(2n)} are linearly independent and the span of γ,,γx(n1)γ, \ldots, γ_x^{(n-1)} is …

2016-08-26abs ↗pdf ↗

Finsler metrics of scalar flag curvature play an important role to show the complexity and richness of general Finsler metrics. In this paper, on an nn-dimensional manifold MM we study the Finsler metric F=F(x,y)F=F(x,y) of scalar flag curvature K=K(x,y){\bf K} = {\bf K}(x,y) and discover some equations K{\bf K} should be satis…

2015-02-28abs ↗pdf ↗

The study examines surfaces in isotropic space with specific Gauss map properties.

problem Understanding surfaces in simply isotropic space with degenerate metric.
method Investigates surfaces with Gauss map coordinates as eigenfunctions of the Laplace-Beltrami operator for minimal and parabolic normals.
result Identifies surfaces characterized by eigenfunction properties of the Gauss map.