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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.

169,181 papers · 148 categories

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48 results for parallel lines

The paper explores parallelisms and spreads in 3D projective space.

problem Characterizing parallelisms and spreads in PG(3,R).
method Introducing topological parallelisms, analyzing their properties and relationships with spreads.
result There are more oriented parallelisms than ordinary parallelisms, and the automorphism group is SO(3).

We show that the fundamental group of the complement of an arrangement of complex lines in the complex plane is a free group if and only if the arrangement is a union of parallel lines.

2009-05-08abs ↗pdf ↗

Characterizes regular parallelisms in 3D space with 2-torus action.

problem Characterizing regular parallelisms in 3D space with 2-torus action.
method Characterization using compactness, equivalence relations, and properties of complex vector spaces.
result There is a 1-dimensional subtorus fixing every parallel class, leading to 2- or 3-dimensional regular parallelisms.

Synthetic splitting theorem for Lorentzian spaces with non-negative curvature.

problem Proving a splitting theorem for globally hyperbolic Lorentzian length spaces with non-negative timelike curvature.
method Synthetic approach using triangle comparison and parallelity of timelike lines.
result Establishes a splitting of a neighborhood of a complete timelike line, leading to global inextendibility.

In this note it is shown that the Maslov Index for pairs of Lagrangian Paths as introduced by Cappell, Lee and Miller appears by parallel transporting elements of (a certain complex line-subbundle of) the symplectic spinorbundle over Euclidean space, when pulled back to an (embedded) Lagrangian submanifold LL, along c…

2008-11-17abs ↗pdf ↗

A cylindrical stretch line is a stretch line, in the sense of Thurston, whose horocyclic lamination is a weighted multicurve. In this paper, we show that two correctly parameterized cylindrical lines are parallel if and only if these lines converge towards the same point in Thurston's boundary of Teichmüller space.

2009-07-10abs ↗pdf ↗

This paper generalizes the envelope of mid-lines to intermediate lines for a plane curve.

problem Understanding the envelope of intermediate lines for a plane curve.
method Using singularity theory techniques to analyze the local behavior of the envelope of intermediate lines.
result The envelope of intermediate lines (EILEIL) is formed by three disconnected sets: AEIL, the curve itself, and IPTL.

In this paper we consider planar polygons with parallel opposite sides. This type of polygons can be regarded as discretizations of closed convex planar curves by taking tangent lines at samples with pairwise parallel tangents. For this class of polygons, we define discrete versions of the area evolute, central symmetr…

2012-10-08abs ↗pdf ↗

In this paper we show that to each planar line arrangement defined over the real numbers, for which no two lines are parallel, one can write down a corresponding relation on Dehn twists that can be read off from the combinatorics and relative locations of intersections. This leads to an alternate proof of Wajnryb's gen…

2011-07-03abs ↗pdf ↗

New parallelisms of 3D projective space found and classified.

problem Classifying parallelisms of 3D projective space with specific automorphism groups.
method Generalized existing constructions to include oriented parallelisms and showed that only Clifford parallelism remains for higher-dimensional automorphism groups.
result Only Clifford parallelism remains for topological parallelisms with automorphism groups of dimension 3 or larger.

The study explores Bertrand and Mannheim curves in 4D Euclidean space for framed curves.

problem Exploring Bertrand and Mannheim curves in 4D Euclidean space for framed curves.
method Defining and investigating Bertrand and Mannheim curves of framed curves in 4D Euclidean space.
result Bertrand and Mannheim curves exist even for framed curves in 4D Euclidean space, contrary to regular curves.

We define pure radiation metrics with parallel rays to be n-dimensional pseudo-Riemannian metrics that admit a parallel null line bundle K and whose Ricci tensor vanishes on vectors that are orthogonal to K. We give necessary conditions in terms of the Weyl, Cotton and Bach tensors for a pseudo-Riemannian metric to be …

2011-07-08abs ↗pdf ↗

We show that every smooth closed curve C immersed in Euclidean 3-space satisfies the sharp inequality 2(P+I)+V >5 which relates the numbers P of pairs of parallel tangent lines, I of inflections (or points of vanishing curvature), and V of vertices (or points of vanishing torsion) of C. We also show that 2(P'+I)+V >3, …

2012-01-06abs ↗pdf ↗

An NQ-manifold is a non-negatively graded supermanifold with a degree 1 homological vector field. The focus of this paper is to define the Wilson loops/lines in the context of NQ-manifolds and to study their properties. The Wilson loops/lines, which give the holonomy or parallel transport, are familiar objects in usual…

2011-08-26abs ↗pdf ↗

Study knot diagrams on a sphere without vertical lines, focusing on minimal crossings.

problem Understanding minimal crossings of knot diagrams on a punctured sphere.
method Mathematical model of string figures using knot diagrams on xyzxyz-space with missing vertical lines, analyzing minimal crossings under Reidemeister moves.
result Minimal number of crossings of knot diagrams on a punctured sphere.

In this technical paper, we present a new formulation of higher parallel transport in strict higher gauge theory required for the rigorous construction of Wilson lines and surfaces. Our approach is based on an original notion of Lie crossed module cocycle and cocycle 1- and 2-gauge transformation with a non standard do…

2014-10-03abs ↗pdf ↗

We prove the existence of a complete, embedded, singly periodic minimal surface, whose quotient by vertical translations has genus one and two ends. The existence of this surface was announced in our paper in {\it Bulletin of the AMS}, 29(1):77--84, 1993. Its ends in the quotient are asymptotic to one full turn of the …

1996-05-17abs ↗pdf ↗

The paper explores almost paracomplex structures on 4-manifolds and their properties.

problem Existence and properties of isometric and anti-isometric almost paracomplex structures on pseudo-Riemannian 4-manifolds.
method Analyzes the conditions under which these structures are parallel and their implications for the scalar curvature and Einstein metrics.
result If an isometric or anti-isometric almost paracomplex structure on a conformally flat manifold is parallel, the scalar curvature of the metric must be zero.

We study the full holonomy group of Lorentzian manifolds with a parallel null line bundle. We prove several results that are based on the classification of the restricted holonomy groups of such manifolds and provide a construction method for manifolds with disconnected holonomy which starts from a Riemannian manifold …

2012-04-25abs ↗pdf ↗

The paper studies singularities on parallels of tangent developable surfaces of frontal curves.

problem Understanding singularities on parallels of tangent developable surfaces.
method Generalization of tangent developable surfaces and parallel deformations for frontal curves in arbitrary dimensions.
result Classification of generic singularities on parallels of tangent developable surfaces for frontal curves in 3 or 4 dimensional Euclidean spaces.

We give a full classification of higher order parallel surfaces in three-dimensional homogeneous spaces with four-dimensional isometry group, i.e. in the so-called Bianchi-Cartan-Vranceanu family. This gives a positive answer to a conjecture formulated in 2002. As a partial result, we prove that totally umbilical surfa…

2006-04-25abs ↗pdf ↗

Consider the standard symplectic $(\RR^{2n}, ω_0)$, a point $p\in\RR^{2n}$ and an immersed closed orientable hypersurface $Σ\subset\RR^{2n}\minus\{p\}$, all in general position. We study the following passage/tangency question: how many lines in $\RR^{2n}$ pass through pp and tangent to ΣΣ parallel to the 1-dimension…

2013-09-04abs ↗pdf ↗

Wilson lines generate positive Laurent polynomials in decorated triangulations.

problem Wilson lines and their coefficients in function algebras.
method Study of Wilson lines on marked surfaces and their matrix coefficients in function algebras.
result Matrix coefficients of Wilson lines give Laurent polynomials with positive integral coefficients.

Anti-self-dual metrics in the (++)(++--) signature which admit a covariantly constant real spinor are studied. It is shown that finding such metrics reduces to solving a fourth order integrable PDE, and some examples are given. The corresponding twistor space is characterised by existence of a preferred non-zero real sec…

2001-02-28abs ↗pdf ↗

Straight lines are a basin of attraction for the elastic flow at least to level 1.9615π.

problem Understanding the basin of attraction for the free boundary free elastic flow.
method Steepest descent gradient flow for elastic energy, numerical evidence.
result Straight lines have a basin of attraction at least to level 1.9615π.

A novel method for parallel transport and geodesics on submanifolds.

problem Understanding parallel transport and geodesics on submanifolds.
method Rolling tangent space to visualize and analyze parallel transport and geodesics.
result Conditions for parallel transport and geodesics are simplified and visualized in the tangent space.

We obtain bounds on the least dimension of an affine space that can contain an nn-dimensional submanifold without any pairs of parallel or intersecting tangent lines at distinct points. This problem is closely related to the generalized vector field problem, non-singular bilinear maps, and the immersion problem for re…

2003-07-03abs ↗pdf ↗

Recent work by Jaffe and Scardicchio has expressed the optical approximation to the Casimir effect as a sum over geometric quantities. The first two authors have developed a technique which uses the complex geometry of the space of oriented affine lines in R3{\Bbb{R}}^3 to describe reflection of rays off a surface. Thi…

2004-06-21abs ↗pdf ↗

We study the structure of the Kauffman algebra of a surface with parameter equal to sqrt(-1). We obtain an interpretation of this algebra as an algebra of parallel transport operators acting on sections of a line bundle over the moduli space of flat connections in a trivial SU(2)-bundle over the surface. We analyse the…

2008-02-06abs ↗pdf ↗

In this paper we consider planar sections and visual contours of co-dimension one affine immersions. The main theorem says that the third order Taylor expansion of the difference between the visual contour and planar section functions is exactly the cubic form. We also consider parameterizations on two dimensional affi…

2010-03-30abs ↗pdf ↗