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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.

168,742 papers · 148 categories

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48 results for geodesic ruled

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.

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.

In this paper, we define a new type of ruled surface called ruled surface by using the alternative frame of a base curve. Then, we study its differential geometric properties such as striction line, distribution parameter, fundamental forms, Gaussian and mean curvatures. Moreover, we find geodesic curvatures, normal cu…

2019-10-15abs ↗pdf ↗

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.

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.

Motivated by a number of recent investigations, we define and investigate the various properties of the ruled surfaces depend on three dimensional Lie groups with a bi-variant metric. We give useful results involving the characterizations of these ruled surfaces. Some special ruled surfaces such as normal surface, bino…

2015-03-09abs ↗pdf ↗

The paper constructs special hypersurfaces in complex space forms.

problem Constructing special hypersurfaces in complex space forms.
method Taking an arbitrary smooth curve in a totally geodesic submanifold and erecting an orthogonal ruling over each point.
result In the n=2n=2 case, the construction yields real-analytic hypersurfaces of cohomogeneity one.

In this study we give definitions and characterizations of transversal surfaces of timelike ruled surfaces. We study some special cases such as the striction curve is a geodesic, an asymptotic line or a line of curvature. Moreover, we obtain developable conditions for transversal surfaces of a timelike ruled surface.

2012-04-05abs ↗pdf ↗

In this paper, we investigate the ruled surfaces generated by a straight line according to rotation minimizing frame (RMF). Using this frame of a straight line, we obtained the necessary and sufficient conditions when the ruled surface is developable. Also, we give some new results and theorems related to be the asympt…

2014-07-01abs ↗pdf ↗

In this paper, on the first, we prove Δr=2HΔr=2H where ΔΔ is the Laplacian operator, r=(r1,r2,r3)r=\left( r_{1},r_{2},r_{3}\right) the position vector field and HH is the mean curvature vector field of a surface S\mathcal{S} in the 3-dimensional Heisenberg group H3.H_{3}. In the second, we classify the ruled surfaces by straight…

2016-05-17abs ↗pdf ↗

In this paper, we study Bertrand surface offsets by considering the dual geodesic trihedron(dual Darboux frame) of the ruled surfaces. We obtain the relationships between the invariants of Bertrand trajectory ruled surfaces. Furthermore, we obtain the conditions for these surface offset to be developable.

2011-08-23abs ↗pdf ↗

In this study, we investigate the existence theorems for timelike ruled surfaces in Minkowski 3-space. We obtain a general system and give the existence theorems for a timelike ruled surface according to Gaussian curvature, distribution parameter and strictional distance. Moreover, we give some special cases such as th…

2012-03-28abs ↗pdf ↗

No closed timelike geodesics in Kerr spacetimes, proving absence of closed causal geodesics.

problem Proving the nonexistence of closed timelike geodesics in Kerr spacetimes.
method Analyzing the Kerr-star spacetime, excluding closed null geodesics and proving the nonexistence of closed timelike geodesics.
result No closed timelike geodesics in Kerr spacetimes.

Proposes a fuzzy rule-based method for data visualization.

problem Preserving neighborhood relationships and handling non-linear manifolds in data visualization.
method Uses a first-order Takagi-Sugeno model with clusters and Geodesic c-means clustering for rule generation and parameter estimation.
result Behaves desirably and performs better than or comparable to other methods.

We consider the Dirichlet Laplacian in infinite two-dimensional strips defined as uniform tubular neighbourhoods of curves on ruled surfaces. We show that the negative Gauss curvature of the ambient surface gives rise to a Hardy inequality and use this to prove certain stability of spectrum in the case of asymptoticall…

2005-11-10abs ↗pdf ↗

With the aid of concrete examples, we consider the question of whether, in the presence of conformal curvature, a conformal geodesic can become trapped in smaller and smaller sets, or phrased informally: are spirals possible? We do not arrive at a definitive answer, but we are able to find situations where this behavio…

2012-04-27abs ↗pdf ↗

In this paper, we study Mannheim surface offsets in dual space. By the aid of the E. Study Mapping, we consider ruled surfaces as dual unit spherical curves and define the Mannheim offsets of the ruled surfaces by means of dual geodesic trihedron (dual Darboux frame). We obtain the relationships between the invariants …

2011-10-05abs ↗pdf ↗

It is shown that parts of planes, helicoids and hyperbolic paraboloids are the only minimal surfaces ruled by geodesics in the three dimensional Riemannian Heisenberg group. It is also shown that they are the only surfaces in the three dimensional Heisenberg group whose mean curvature is zero with respect to both of th…

2009-06-06abs ↗pdf ↗

In this paper, we study the spherical indicatrices of W-direction curves in three dimensional Euclidean space which were defined by using the unit Darboux vector field W of a Frenet curve, in [11]. We obtain the Frenet apparatus of these spherical indicatrix curves and the characterizations of being general helix and s…

2015-06-12abs ↗pdf ↗

The study characterizes constant curvature manifolds using ruled surfaces.

problem Characterizing manifolds of constant curvature using ruled surfaces.
method Investigating ruled surfaces in 3d Riemannian manifolds, finding stiction curve, distribution parameter, and fundamental forms.
result Identifies necessary and sufficient conditions for extrinsically flat surfaces to be ruled and proves manifold properties.

We construct a Kähler structure (J,Ω,G{\mathbb{J}},Ω,{\mathbb{G}}) on the space L(H3){\mathbb{L}}({\mathbb{H}}^3) of oriented geodesics of hyperbolic 3-space H3{\mathbb{H}}^3 and investigate its properties. We prove that (L(H3),J){\mathbb{L}}({\mathbb{H}}^3),{\mathbb{J}}) is biholomorphic to ${\mathbb{P}}^1\times{\mathbb{P}}^1-\ba…

2007-02-09abs ↗pdf ↗

Study shows only hyperplanes in Heisenberg groups have zero curvature.

problem Understanding Bernstein problem in higher dimensional Heisenberg groups.
method Sub-Riemannian characterization of ruling property and study of geodesics.
result Only hyperplanes have zero horizontal symmetric second fundamental form in Heisenberg groups.

Study of curves and surfaces in Riemannian spaces making a constant angle with a parallel transported direction.

problem Understanding geometric properties of curves and surfaces in Riemannian spaces.
method Developing a theoretical framework to study curves and surfaces by their angle with a parallel transported vector field.
result Surfaces making a constant angle with a parallel transported direction are extrinsically flat ruled surfaces.

The study constructs associative 3-folds in squashed 3-Sasakian manifolds.

problem Understanding associative submanifolds in squashed 3-Sasakian manifolds.
method Analyzes foliations and geodesic ruled associative 3-folds correspondence.
result Infinitely many topological types of non-trivial associative 3-folds constructed.

We give the complete solution to the local diffeomorphism classification problem of generic singularities which appear in tangent surfaces, in as wider situations as possible. We interpret tangent geodesics as tangent lines whenever a (semi-)Riemannian metric, or, more generally, an affine connection is given in an amb…

2016-02-08abs ↗pdf ↗

The paper studies horizontal semimartingales on Riemannian manifolds and their connections to Euclidean spaces.

problem Stochastic lifts and anti-developments of semimartingales on Riemannian manifolds.
method Using stochastic differential geometry with jumps, the paper establishes correspondences between discontinuous semimartingales and their lifts.
result The paper extends previous results to include geodesics and small jumps, enabling the construction of martingales from local martingales.

The paper analyzes discrete approximations to minimize curve length in Euclidean space.

problem Minimizing the length of curves between two sets in Euclidean space.
method Finite differences and numerical integration for discrete approximations.
result The squared length of the reconstructed curve converges to the squared minimal length with rate O(N1/2)O(N^{-1/2}).

Wire billiard is defined by a smooth embedded closed curve of non-vanishing curvature kk in Rn\mathbb{R}^n (a wire). For a class of curves, that we call nice wires, the wire billiard map is area preserving twist map of the cylinder. In this paper we are investigating whether the basic features of conventional planar b…

2019-05-31abs ↗pdf ↗

Extends DCP framework to Hadamard manifolds for geodesically convex functions.

problem Verifying convexity in nonlinear programs on Hadamard manifolds.
method Introduces Disciplined Geodesically Convex Programming (DGCP) framework, defining compositions and transformations for geodesically convex functions.
result Allows verification of geodesic convexity for a broader range of functions, including statistical estimators and matrix-valued optimization.

New para-Kähler structure found in geodesic space.

problem Constructing a new para-Kähler structure in geodesic space.
method Developed a new para-Kähler metric and studied its properties in the space of oriented geodesics.
result The space of oriented geodesics in hyperbolic n-space is minimally isometric embedded with the constructed metric.

Proposes Geodesic Integrated Gradients (GIG) for more accurate feature attributions in deep networks.

problem Flawed attributions using straight paths from Integrated Gradients (IG).
method Introduces a model-induced Riemannian metric and computes attributions along geodesics.
result GIG produces more faithful attributions than IG on benchmarks.

A directed curve is a possibly singular curve with well-defined tangent lines along the curve. Then the tangent surface to a directed curve is naturally defined as the ruled surface by tangent geodesics to the curve, whenever any affine connection is endowed with the ambient space. In this paper the local diffeomorphis…

2016-07-29abs ↗pdf ↗

We consider the Dirichlet Laplacian in unbounded strips on ruled surfaces in any space dimension. We locate the essential spectrum under the condition that the strip is asymptotically flat. If the Gauss curvature of the strip equals zero, we establish the existence of discrete spectrum under the condition that the curv…

2019-06-06abs ↗pdf ↗