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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.

169,341 papers · 148 categories

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48 results for non-null ruled surfaces

Formula for winding numbers on non-null-homotopic curves on surfaces.

problem Determining winding numbers for non-null-homotopic curves on surfaces.
method Generalized a Whitney-type formula for winding numbers of non-null-homotopic curves on aspherical surfaces.
result Formula for winding numbers on non-null-homotopic curves on aspherical surfaces.

In this study, non-null Frenet-Mannheim curves and non-null Weakened Mannheim curves are investigated in Minkowski 3-space. Some characterizations for this curves are obtained.

2012-04-13abs ↗pdf ↗

In this paper, we investigate the similarity transformations in the Minkowski-n space. We study the geometric invariants of non-null curves under the similarity transformations. Besides, we extend the fundamental theorem for a non-null curve according to a similarity motion. We determine all non-null self-similar curve…

2014-08-07abs ↗pdf ↗

The paper connects hyperbolic spinors to non-null framed curves in Minkowski 3-space.

problem Understanding geometric properties of non-null framed curves.
method Developed new adapted frames for non-null framed curves and investigated their hyperbolic spinor representations.
result Found geometric results and interpretations for non-null framed curves.

This paper studies ruled real hypersurfaces in indefinite complex projective space.

problem Characterizing and classifying ruled real hypersurfaces in indefinite complex projective space.
method Introduced and studied ruled real hypersurfaces with maximal holomorphic distribution integrable and leaves totally geodesic holomorphic hyperplanes. Detailed shape operator computation and method of construction by gluing totally geodesic hyperplanes along a curve.
result Classification of all minimal ruled real hypersurfaces in terms of three main families of curves.

Two holomorphic Hopf differentials for surfaces of non-null parallel mean curvature vector in S^2xS^2 and H^2xH^2 are constructed. A 1:1 correspondence between these surfaces and pairs of constant mean curvature surfaces of S^2xR and H^2xR is established. Using that, surfaces with vanishing Hopf differentials (in parti…

2008-07-11abs ↗pdf ↗

In this paper we study the non-geodesic non-null biharmonic curves in 3-dimensional hyperbolic Heisenberg group. We prove that all of the non-geodesic non-null biharmonic curves in 3-dimensional hyperbolic Heisenberg group are helices. Moreover, we obtain explicit parametric equations for non-geodesic non-null biharmon…

2011-03-03abs ↗pdf ↗

Improved sequential tests detect anomalies faster in multi-stream auditing.

problem Efficiently auditing machine learning systems across multiple data streams.
method Developed new sequential tests using merging martingales and averaging/products rules.
result Balanced tests achieve optimal stopping times in sparse and dense alternatives.

The study characterizes canal hypersurfaces formed by non-null curves with parallel frame in Minkowski space-time.

problem Characterizing canal hypersurfaces in Minkowski space-time.
method Obtained canal hypersurfaces by pseudo hyperspheres or pseudo hyperbolic hyperspheres with parallel timelike normal vector field.
result Gaussian curvature, mean curvature, and principal curvatures of canal hypersurfaces were derived.

Electrostatic systems with specific tensors are locally conformally flat.

problem Understanding the geometry of electrostatic systems with special tensors.
method Proving local conformal flatness for electrostatic manifolds with divergence-free Bach tensor.
result Three-dimensional electrostatic manifolds with divergence-free Bach tensor are locally conformally flat.

Given a polyhedral surface, assume that it is prohibited to change the shape and size of any face but it is permissible to change the dihedral angles between the faces. A polyhedral surface is said to be flexible if it is possible to change its shape under the above restrictions. We prove that flexible polyhedral surfa…

2001-11-01abs ↗pdf ↗

In this study, we give the relationships between the conical curvatures of ruled surfaces drawn by the unit vectors of the ruling, central normal and central tangent of a regular ruled surface in the Euclidean -space. We obtain the differential equations characterizing slant ruled surfaces and if the reference ruled su…

2013-11-27abs ↗pdf ↗

In this study, we define some new types of ruled surfaces called slant ruled surfaces. We give some characterizations for a regular ruled surface to be a slant ruled surface in Euclidean 3- space. We show that if the slant ruled surface is developable then the striction curve is a general helix or a slant helix accordi…

2013-11-04abs ↗pdf ↗

Study ruled minimal surfaces in solvable Lie groups, classifying and constructing examples.

problem Classifying and constructing ruled minimal surfaces in solvable Lie groups.
method Classification and construction of ruled surfaces, parametrization for specific cases.
result Classification and construction of ruled minimal surfaces in solvable Lie groups.

In this study, we introduce Darboux slant ruled surfaces in the Euclidean 3-space which is defined by the property that the Darboux vector of orthonormel frame of ruled surface makes a constant angle with a fixed, non-zero direction. We obtain the characterizations of Darboux slant ruled surfaces regarding the conical …

2013-11-04abs ↗pdf ↗

New type of ruled surfaces studied with properties and examples.

problem Characterizing and understanding new types of ruled surfaces.
method Definition of a new orthonormal frame, calculation of Gaussian and mean curvatures, analysis of Weingarten map and geodesic properties.
result Conditions for an OT-surface to be flat or minimal are derived, and examples of helices and slant helices are provided.

In this paper, using the classifications of timelike and spacelike ruled surfaces, we study the Mannheim offsets of timelike ruled surfaces in Minkowski 3-space. Firstly, we define the Mannheim offsets of a timelike ruled surface by considering the Lorentzian casual character of the offset surface. We obtain that the M…

2009-06-11abs ↗pdf ↗

The Lamarle Formula, given by Kruppa in \cite{Kr}, is known as a relationship between the Gaussian curvature and the distribution parameter of a ruled surface in the surface theory. The ruled surfaces were investigated in 3 different classes with respect to the character of base curves and rulings, \cite{Tu1},\cite{Tu2…

2010-01-05abs ↗pdf ↗

We classify ruled minimal surfaces in R3\Bbb R^3 with density ez.e^z. It is showed that there is no noncylindrical ruled minimal surface and there is a family of cylindrical ruled minimal surfaces in R3\Bbb R^3 with density ez.e^z. It is also proved that all translation minimal surfaces are ruled.

2009-01-25abs ↗pdf ↗

Study on ruled surfaces over elliptic curves, focusing on Poisson deformations.

problem Obstructedness or unobstructedness of Poisson deformations of ruled surfaces.
method Analysis of ruled surfaces over elliptic curves, focusing on Poisson deformations.
result Determination of obstructedness or unobstructedness of Poisson deformations.

For Lorentzian 2-manifolds (Σ1,g1)(Σ_1,g_1) and (Σ2,g2)(Σ_2,g_2) we consider the two product para-Kähler structures (Gε,J,Ωε)(G^ε,J,Ω^ε) defined on the product four manifold Σ1×Σ2Σ_1\timesΣ_2, with ε=±1ε=\pm 1. We show that the metric GεG^ε is locally conformally flat (resp. Einstein) if and only if the Gauss curvatures κ1,κ2κ_1,κ_2 of $g_1,g_…

2014-03-03abs ↗pdf ↗

In this paper, we consider non developable ruled surface with spacelike ruling, timelike ruling, respectively. We give the relations between the structure functions with the curvature and torsion of the striction line of the timelike and spacelike non developable ruled surfaces. Also, we have calculated the gaussian an…

2014-03-05abs ↗pdf ↗

Defines new ruled surfaces using alternative frames and analyzes their geometric properties.

problem Analyzing geometric properties of new ruled surfaces.
method Using alternative frames to define new ruled surfaces and studying their differential geometric properties.
result Geodesic curvatures, normal curvatures, and geodesic torsions of the base curve and striction line are found.

This study examines geometric properties and offsets of slant timelike-ruled surfaces.

problem Geometric properties and offsets of slant timelike-ruled surfaces in Minkowski 3-space.
method Derivation of parametric formulation, conditions for coaxial alignment, examination through Blaschke and Darboux frames.
result Conditions ensuring the coaxial alignment of the central normal with the ruling direction of the offset surface.

Study on evolutes and focal surfaces of pseudo-spherical framed immersions in anti-de Sitter space.

problem Investigating singularities of evolutes and focal surfaces of pseudo-spherical framed immersions.
method Introduced pseudo-spherical non-null framed curves, defined moving frames, and analyzed evolutes and focal surfaces.
result Evolutes of pseudo-spherical framed immersions are the sets of singular points of their focal surfaces.

Paper classifies ruled surfaces in Lorentz-Minkowski space for a specific flow.

problem Classifying ruled surfaces in Lorentz-Minkowski space.
method Examining homothetic self-similar solutions of the inverse mean curvature flow.
result Existence of two classes of non-cylindrical homothetic solitons.

The paper studies skew ruled surfaces with specific normalization properties.

problem Characterizing skew ruled surfaces with relative normalizations.
method Analyzes skew ruled surfaces in E3\mathbb{E}^{3} with a specific form of support function.
result Investigates properties of Tchebychev and support vector fields for these surfaces.

The paper classifies ruled surfaces in Lorentz-Minkowski space that are stationary for the moment of inertia.

problem Classifying ruled surfaces in Lorentz-Minkowski space that are stationary for the moment of inertia.
method Maximum principle applications, classification based on causal character of rulings.
result Planes are the only cylindrical stationary surfaces. For non-cylindrical surfaces, classification depends on the causal character of the rulings.

Defines and analyzes generalized normal ruled surfaces of curves in 3D space.

problem Understanding the geometry of generalized normal ruled surfaces.
method Calculates Gaussian and mean curvatures to determine surface properties and examines curve conditions.
result Determines when surfaces are flat or minimal and identifies specific curve types.

Study on Kähler metrics on ruled surfaces, proving existence and non-existence.

problem Existence and non-existence of Kähler metrics on minimal ruled surfaces.
method Analysis of twisted and coupled constant scalar curvature Kähler metrics.
result Bound for Chen-Cheng invariant on ruled surfaces.

This article concerns exact results on the minimum number of colors of a Fox coloring over the integers modulo r, of a link with non-null determinant. Specifically, we prove that whenever the least prime divisor of the determinant of such a link and the modulus r is 2, 3, 5, or 7, then the minimum number of colors is 2…

2010-01-08abs ↗pdf ↗

In this paper, we study the special curves and ruled surfaces on helix hypersurface whose tangent planes make a constant angle with a fixed direction in Euclidean n-space Besides, we observe some special ruled surfaces in and give requirement of being developable of the ruled surface. Also, we investigate the helix sur…

2012-04-12abs ↗pdf ↗

Study of timelike surfaces with time-minimizing rulings in Newtonian and relativistic spacetimes.

problem Understanding time-minimizing paths in spacetime geometries.
method Constructing timelike surfaces ruled by geodesics of Finsler or Jacobi metrics.
result Explicit examples of brachistochrone-ruled timelike surfaces in Minkowski and Schwarzschild spacetimes.