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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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48 results for null quadric

The study proves a strong parametric h-principle for minimal surfaces.

problem Proving a parametric h-principle for minimal surfaces.
method Using a parametric h-principle due to Forstneric and Larusson.
result The space of complete nonflat conformal minimal immersions has the same homotopy type as the space of continuous maps.

We study the moduli space of null curves in Klein's quartic in the four-dimensional (complex) projective plane using methods developed by Robert Bryant. As a consequence, we show that minimal surfaces with 99 embedded planar ends do not exist and formulate some conjectures about the previous moduli space.

2019-05-13abs ↗pdf ↗

These are notes on some algebraic geometry of complex projective curves, together with an application to studying the contact curves in CP^3 and the null curves in the complex quadric Q^3 in CP^4, related by the well-known Klein correspondence. Most of this note consists of recounting the classical background. The main…

2019-05-15abs ↗pdf ↗

We give a detailed account of the geometric correspondence between a smooth complex projective quadric hypersurface Qn\mathcal{Q}^n of dimension n3n \geq 3, and its twistor space PT\mathbb{PT}, defined to be the space of all linear subspaces of maximal dimension of Qn\mathcal{Q}^n. Viewing complex Euclidean space $\mat…

2015-05-26abs ↗pdf ↗

Quaternionic approach to conformal superminimal surfaces in four-space

problem Developing a quaternionic approach to conformal superminimal surfaces in Euclidean four-space
method Using the Weierstrass representation and factorizing null curves
result An explicit quaternionic reformulation of the superminimality condition

We study CR quadrics satisfying a symmetry property (S~)(\tilde S) which is slightly weaker than the symmetry property (S)(S), recently introduced by W. Kaup, which requires the existence of an automorphism reversing the gradation of the Lie algebra of infinitesimal automorphisms of the quadric. We characterize quadrics s…

2010-11-15abs ↗pdf ↗

Classifies real rational knots and curves in a specific quadric space.

problem Classifying real rational knots and curves in a quadric space of signature (3,2)(3,2).
method Classification through a study of real rational curves of low degree in the quadric.
result Provides representatives of all real rational knots of degree 5\leq 5 in the quadric.

Study finds Stäckel equivalence for superintegrable systems via invariant quadrics.

problem Understanding Stäckel equivalence in superintegrable systems.
method Using invariant quadrics to determine Stäckel classes of superintegrable systems.
result Stäckel classes of superintegrable systems can be derived from associated invariant quadrics.

A fake quadric is a smooth projective surface that has the same rational cohomology as a smooth quadric surface but is not biholomorphic to one. We provide an explicit classification of all irreducible fake quadrics according to the commensurability class of their fundamental group. To accomplish this task, we develop …

2015-04-17abs ↗pdf ↗

We provide a generalization of Bianchi's Bäcklund transformation from 2-dimensional quadrics to higher dimensional quadrics. The starting point of our investigation is the higher dimensional (infinitesimal) version of Bianchi's main four theorems on the theory of deformations of quadrics and Bianchi's treatment of the …

2008-08-14abs ↗pdf ↗

In trying to provide explicit deformations of quadrics the starting point of our investigation is to use Bianchi's link between real deformations of totally real regions of real paraboloids and various totally real forms of the sine-Gordon equation coupled with Bianchi's simple observation that the vacuum soliton of th…

2008-08-14abs ↗pdf ↗

The paper classifies Hopf hypersurfaces in complex quadrics with commuting Jacobi operators.

problem Characterizing Hopf real hypersurfaces with commuting Jacobi operators.
method Investigating the commuting property between normal and structure Jacobi operators.
result A remarkable classification of Hopf real hypersurfaces in the complex quadric with commuting Jacobi operators.

Researchers find explicit Bäcklund transforms for specific quadrics.

problem Isometric deformations of diagonal higher dimensional quadrics without center.
method Explicitly found Bäcklund transforms using the Bianchi Permutability Theorem and 3-moving Möbius configuration.
result Explicit solutions can be iterated with arbitrary constants.

Canonical parametrisations of classical confocal coordinate systems are introduced and exploited to construct non-planar analogues of incircular (IC) nets on individual quadrics and systems of confocal quadrics. Intimate connections with classical deformations of quadrics which are isometric along asymptotic lines and …

2019-08-02abs ↗pdf ↗

The paper classifies Hopf hypersurfaces with constant curvatures on complex quadrics.

problem Classifying Hopf hypersurfaces with specific curvature properties.
method Analyzing hypersurfaces on complex quadrics with at most five distinct constant principal curvatures.
result All classified hypersurfaces are open parts of homogeneous examples.

We establish a link between Archimedes' method of integration for calculating areas, volumes and centers of mass of segments of parabolas and quadrics of revolution by factorization via the moments of a balance and an integration technique for a particular integrable system, namely Bianchi's Bäcklund transformation for…

2007-09-26abs ↗pdf ↗

We discuss holomorphic isometric embeddings of the projective line into quadrics using a generalisation of the theorem of do Carmo--Wallach to provide a description of their moduli spaces up to image and gauge--equivalence. Moreover, we show rigidity of the real standard map from the projective line into quadrics.

2014-08-14abs ↗pdf ↗

Confocal quadrics capture (encode) and geometrize spectral properties of symmetric operators. Certain metric-projective properties of confocal quadrics (most of them established in the first half of the XIXth^{\mathrm{th}} century) {\it carry out} (stick and transfer) by rolling to and influence surfaces {\it applicabl…

2006-12-13abs ↗pdf ↗

We prove here that when all planes transverse and nearly perpendicular to the axis of a surface of revolution intersect it in loops having central symmetry, the surface must be quadric. It follows that the quadrics are the only surfaces of revolution without skewloops. Similar statements hold for hypersurfaces of revol…

2007-12-17abs ↗pdf ↗

Paper proves non-existence of certain hypersurfaces in complex quadric.

problem Non-existence of Hopf real hypersurfaces with parallel normal Jacobi operator.
method Introducing C\mathcal C-parallel and Reeb parallel normal Jacobi operators, proving non-existence theorems.
result Non-existence of Hopf real hypersurfaces with C\mathcal C-parallel normal Jacobi operator.

The paper classifies and determines properties of specific hypersurfaces in complex hyperbolic quadrics.

problem Analyzing Hopf hypersurfaces with constant principal curvatures in complex hyperbolic quadrics.
method Classification and determination of principal curvatures for hypersurfaces with different numbers of distinct curvatures.
result Classification and determination of principal curvatures for Hopf hypersurfaces with up to four distinct values.

In this paper, we study ruled surfaces and quadrics in the 3-dimensional Euclidean space which are of finite IIIIII-type, that is, they are of finite type, in the sense of B.-Y. Chen, with respect to the third fundamental form. We show that helicoids and spheres are the only ruled and quadric surfaces of finite IIIIII-ty…

2017-10-19abs ↗pdf ↗

This study classifies quadric surfaces in 3-sphere as Weingarten surfaces.

problem Extension of quadric surfaces of revolution to 3-sphere.
method Rigorous classification and characterization using spherical angular momentum.
result Spherical ellipsoids, hyperboloids, and paraboloids are Weingarten surfaces with a specific cubic relation between principal curvatures.

We provide the first explicit examples of deformations of higher dimensional quadrics: a straightforward generalization of Peterson's explicit 1-dimensional family of deformations in C3\mathbb{C}^3 of 2-dimensional general quadrics with common conjugate system given by the spherical coordinates on the complex sphere $\…

2008-02-18abs ↗pdf ↗

The quadric ansatz solves dKP equations in arbitrary dimensions, leading to Einstein-Weyl structures.

problem Characterizing solutions of the dispersionless KP equation in arbitrary dimensions.
method Quadric ansatz for the dKP equation, constructing Einstein-Weyl spaces.
result Explicit new family of Einstein-Weyl spaces constructed and characterized.

Adapts stereographic projection for ellipsoid and elliptic paraboloid.

problem Projecting quadric surfaces using stereographic method.
method Adapted stereographic projection for ellipsoid and elliptic paraboloid, analyzing geometric properties and challenges.
result Established results on eccentricities, curvatures, arc length, and areas of intersections and projections.

We classify real hypersurfaces with isometric Reeb flow in the complex quadrics Q^m for m > 2. We show that m is even, say m = 2k, and any such hypersurface is an open part of a tube around a k-dimensional complex projective space CP^k which is embedded canonically in Q^{2k} as a totally geodesic complex submanifold. A…

2013-01-03abs ↗pdf ↗

Minimal Lagrangian surfaces in complex hyperbolic quadric via loop group method.

problem Characterizing and constructing minimal Lagrangian surfaces in complex hyperbolic quadric.
method Loop of flat connections, isometric deformations, DPW-type representation.
result Explicit examples of minimal Lagrangian surfaces, including catenoid-type examples.

The study characterizes quadrics among affine hyperspheres based on centroid collinearity of sections.

problem Characterizing quadrics among affine hyperspheres based on section centroid collinearity.
method Extending Meyer and Reisner's theorem to unbounded convex sets and identifying additional assumptions.
result Ellipsoids, paraboloids, and one sheet of a two-sheeted hyperboloid are the only quadrics satisfying the centroid collinearity condition.