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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.

168,657 papers · 148 categories

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265277103 · Jun 202019922001200920172026
48 results for Euclidean nets

Geodesic nets on Riemannian manifolds form a natural class of stationary objects generalizing geodesics. Yet almost nothing is known about their classification or general properties even when the ambient Riemannian manifold is the Euclidean plane or the round 22-sphere. In the first half of this paper we survey some r…

2019-03-31abs ↗pdf ↗

We consider nn-dimensional discrete motions such that any two neighbouring positions correspond in a pure rotation ("rotating motions"). In the Study quadric model of Euclidean displacements these motions correspond to quadrilateral nets with edges contained in the Study quadric ("rotation nets"). The main focus of ou…

2010-04-08abs ↗pdf ↗

We prove that a geodesic net with three boundary (= unbalanced) vertices on a non-positively curved plane has at most one balanced vertex. We do not assume any a priori bound for the degrees of unbalanced vertices. The result seems to be new even in the Euclidean case. We demonstrate by examples that the result is not …

2018-03-10abs ↗pdf ↗

Integrable nets described with curvature relations to pseudospherical surfaces.

problem Describing integrable curve nets and their geometric properties.
method Overview of second-order invariants, specific example of concordant nets, and construction of pseudospherical surfaces.
result Concordant Chebyshev nets correspond to pairs of pseudospherical surfaces.

In the present study we consider knotted spheres in Euclidean 44-space E4 \mathbb{E}^{4}. Firstly, we give some basic curvature properties of knotted spheres in E4 \mathbb{E}^{4}. Further, we obtained some results related with the conjugate nets and Laplace transforms of these kind of surfaces.

2016-08-17abs ↗pdf ↗

We study Christoffel and Darboux transforms of discrete isothermic nets in 4-dimensional Euclidean space: definitions and basic properties are derived. Analogies with the smooth case are discussed and a definition for discrete Ribaucour congruences is given. Surfaces of constant mean curvature are special among all iso…

1996-11-25abs ↗pdf ↗

We investigate some characteristic properties of specific Weingarten surfaces in the three-dimensional Euclidean space using the nets of the lines of curvature resp. the asymptotic lines on both central surfaces of them.

2015-11-24abs ↗pdf ↗

A Clifford algebra model for M"obius geometry is presented. The notion of Ribaucour pairs of orthogonal systems in arbitrary dimensions is introduced, and the structure equations for adapted frames are derived. These equations are discretized and the geometry of the occuring discrete nets and sphere congruences is disc…

1998-02-27abs ↗pdf ↗

Rigidity theorem for discrete metric spaces embedded in Riemannian surfaces.

problem Understanding the rigidity of discrete metric spaces embedded in Riemannian surfaces.
method Proving that certain discrete metric spaces are rigidly embedded in the Euclidean plane or other Riemannian surfaces.
result Riemannian embeddings of certain discrete metric spaces are rigid, meaning they cannot be deformed without changing distances.

Novel bistable structures made from four-bar linkages, proving existence and construction.

problem Existence and construction of bistable mechanical structures composed of four-bar linkages.
method Geometric construction starting from infinitesimally flexible quad nets, applying Whiteley de-averaging.
result Construction of bistable structures from well-known quad nets, allowing control of geometric parameters.

Skew parallelogram nets factorize, encompassing discrete differential geometry.

problem Factorization of polynomials in discrete differential geometry.
method Lax representation, Bäcklund transformations, factorization of polynomials.
result Skew parallelogram nets encompass all systems with polynomial representations.

In this paper are studied the nets of principal curvature lines on surfaces embedded in Euclidean 33-space near their end points, at which the surfaces tend to infinity. This is a natural complement and extension to smooth surfaces of the work of Garcia and Sotomayor (1996), devoted to the study of principal curvature…

2005-01-24abs ↗pdf ↗

We study the problem posed by F. Burstall of developing a theory of isothermic Euclidean submanifolds of dimension greater than or equal to three. As a natural extension of the definition in the surface case, we call a Euclidean submanifold {\it isothermic} if it is locally the image of a conformal immersion of a Riema…

2004-01-04abs ↗pdf ↗

New discrete cmc surfaces defined from sphere packings and combinatorics.

problem Creating constant mean curvature surfaces from discrete data.
method Discrete cmc surfaces defined via sphere packings and combinatorial patterns.
result Construction of discrete cmc surfaces from orthogonal ring patterns.

The paper explores discrete isothermic nets using checkerboard patterns in quadrilateral nets.

problem Defining and understanding discrete isothermic nets in quadrilateral nets.
method Using checkerboard patterns and discrete differential geometry to define and analyze isothermic nets.
result The class of isothermic nets is invariant under dualization and Moebius transformations.

In this paper, we introduce transformations of deep rectifier networks, enabling the conversion of deep rectifier networks into shallow rectifier networks. We subsequently prove that any rectifier net of any depth can be represented by a maximum of a number of functions that can be realized by a shallow network with a …

2017-03-30abs ↗pdf ↗

New framework improves robustness of implicit neural networks.

problem Ill-posedness and convergence instability in implicit neural networks.
method NEMON framework based on contraction theory for \ell_{\infty} norm, including well-posedness condition, average iteration, and input-output Lipschitz constant regularization.
result Improved accuracy and robustness of implicit models with smaller input-output Lipschitz bounds.

We discuss discretization of Koenigs nets (conjugate nets with equal Laplace invariants) and of isothermic surfaces. Our discretization is based on the notion of dual quadrilaterals: two planar quadrilaterals are called dual, if their corresponding sides are parallel, and their non-corresponding diagonals are parallel.…

2007-09-21abs ↗pdf ↗

We study local and global approximations of smooth nets of curvature lines and smooth conjugate nets by respective discrete nets (circular nets and planar quadrilateral nets) with infinitesimal quads. It is shown that choosing the points of discrete nets on the smooth surface one can obtain second-order approximation g…

2007-06-21abs ↗pdf ↗

Circular nets with spherical parameter lines have geometric properties related to Darboux cyclides and terminating Laplace sequences.

problem Discretizing surfaces with spherical curvature lines.
method Lie-geometric discretisation in terms of principal contact element nets.
result Circular nets with two families of spherical parameter lines are related to Darboux cyclides.

Smart Close-out Netting aims to automate close-out netting processes.

problem Inefficiencies in close-out netting processes for financial institutions.
method Standardisation and automation of legal and regulatory processes using a data-driven framework and controlled natural language.
result Standardisation and automation can improve close-out netting processes for prudentially regulated financial institutions.

This paper considers the power of deep neural networks (deep nets for short) in realizing data features. Based on refined covering number estimates, we find that, to realize some complex data features, deep nets can improve the performances of shallow neural networks (shallow nets for short) without requiring additiona…

2019-01-01abs ↗pdf ↗

Supercyclides are surfaces with a characteristic conjugate parametrization consisting of two families of conics. Patches of supercyclides can be adapted to a Q-net (a discrete quadrilateral net with planar faces) such that neighboring surface patches share tangent planes along common boundary curves. We call the result…

2014-12-23abs ↗pdf ↗

A geodesic net with 4 boundary vertices and 25 balanced vertices is constructed.

problem Constructing geodesic nets with specific vertex types and properties.
method Novel approach to increase the number of balanced vertices from 16 to 25.
result First net with four boundary vertices and 25 balanced vertices, including non-symmetric balanced vertices.

In this paper, we use replica analysis to determine the investment strategy that can maximize the net present value for portfolios containing multiple development projects. Replica analysis was developed in statistical mechanical informatics and econophysics to evaluate disordered systems, and here we use it to formula…

2018-10-15abs ↗pdf ↗

In this paper we establish a relationship between geodesic nets and critical points of the distance function. We bound the number of balanced points for certain minimizing geodesic nets on manifolds homeomorphic to the nn-sphere. We also bound the length of certain minimizing geodesic nets.

2019-05-17abs ↗pdf ↗