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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.

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48 results for Christoffel symbols

Type A surfaces are the locally homogeneous affine surfaces which can be locally described by constant Christoffel symbols. We address the issue of the geodesic completeness of these surfaces: we show that some models for Type A surfaces are geodesically complete, that some others admit an incomplete geodesic but model…

2016-11-03abs ↗pdf ↗

The article approximates solutions to the Beltrami equation using similarity surfaces.

problem Approximating solutions to the Beltrami equation.
method Constructing similarity surfaces from polygons and analyzing their conformal uniformization.
result Holomorphic dependence of Christoffel symbols on polygons and convergence to a specific affine connection.

In this paper, we study the inverse surfaces in 3-dimensional Euclidean space E3\mathbb{E}^{3}. We obtain some results relating Christoffel symbols, the normal curvatures, the shape operators and the third fundamental forms of the inverse surfaces

2012-05-16abs ↗pdf ↗

Generalized Lagrange-Weyl structures and compatible connections are introduced as a natural generalization of similar notions from Riemannian geometry. Exactly as in Riemannian case, the compatible connection is unique if certain symmetry conditions with respect to vertical and horizontal Christoffel symbols are impose…

2006-05-24abs ↗pdf ↗

Geometrically represents path integral reduction Jacobian for interacting systems.

problem Quantizing a model mechanical system with dependent coordinates.
method Geometric representation using scalar curvature and Christoffel symbols in a nonholonomic basis.
result Found a geometric representation for the path integral reduction Jacobian.

In the present article the geometry of semi-Riemannian manifolds with nonholonomic constraints is studied. These manifolds can be considered as analogues to the sub-Riemannian manifolds, where the positively definite metric is substituted by a nondegenerate metric. To study properties of the exponential map the Christo…

2009-01-11abs ↗pdf ↗

In this paper, we define the inverse surface of a tangent developable surface with respect to the sphere S_{c}(r) with the center cE3c\in \mathbb{E}^{3} and the radius r in 3-dimensional Euclidean space E3\mathbb{E}^{3}. We obtain the curvatures, the Christoffel symbols and the shape operator of this inverse surface by …

2012-05-16abs ↗pdf ↗

We present the non-trivial example how to generate non-Euclidean geometries from associative unital algebras. We consider bundles of the sphere of the degenerate non-Eucleadian space and its two models. The first (conformal) model is obtained by the mapping S onto a plane pass through the origin. It is analogous to the…

2009-12-09abs ↗pdf ↗

The paper solves a generalized Christoffel-Minkowski problem using a curvature flow.

problem Solving the (p,q)-Christoffel-Minkowski problem.
method Investigating the problem via an expanding curvature flow.
result Existence and uniqueness of smooth solutions to the (p,q)-Christoffel-Minkowski problem.

Given a space it is easy to obtain the system of geodesic equations on it. In this paper the inverse problem of reconstructing the space from the geodesic equations is addressed. A procedure is developed for obtaining the metric tensor from the Christoffel symbols. The procedure is extended for determining if a second …

2007-11-08abs ↗pdf ↗

A new approach to Riemannian geometry using embedded and submersion structures.

problem Studying Riemannian geometry on manifolds embedded in Euclidean spaces.
method Identifying tangent bundles with subbundles of trivial bundles, extending metrics, and defining submersed ambient structures.
result Simplified formulas for Christoffel symbols and Riemannian curvature in embedded and submersion structures.

Classifies 3-braids from choreographic motions on Lissajous curves, linking them to mapping classes and geodesics.

problem Classifying 3-braids from choreographic motions on Lissajous curves.
method Parametrization in terms of levels and slopes, using dilatation and geodesic cutting sequences.
result Dilatation of pseudo-Anosov mapping classes increases with level or slope.

Paper solves Christoffel-Minkowski problem in hyperbolic space.

problem Prescribing kk-th horospherical pp-surface area measure of hh-convex domains in hyperbolic space.
method Considered a fully nonlinear equation and used the full rank theorem with a viscosity approach.
result Existence of uniformly hh-convex solution under appropriate assumptions.

This paper solves the Christoffel problem in hyperbolic space and its equivalent on spheres.

problem Prescribing curvatures for convex hypersurfaces in hyperbolic space.
method Proving a full rank theorem to establish the existence of solutions.
result Existence of solutions to the Christoffel problem and its equivalent Nirenberg-Kazdan-Warner problem on spheres.

Paper solves Christoffel-Minkowski and Weingarten curvature problems in hyperbolic space.

problem Christoffel-Minkowski and Weingarten curvature problems in hyperbolic space.
method Proved existence of solutions using a new full rank theorem.
result Existence of smooth, origin-symmetric, strictly horospherically convex solutions.

A proof that hyperbolic plane cannot be immersed in Euclidean 3-space.

problem Proving the impossibility of isometrically immersing the hyperbolic plane in Euclidean 3-space.
method Applying ideas from undergraduate mathematics, including moving frames and connection forms, to simplify the proof.
result A key transition from principal directions to asymptotic directions simplifies the proof and yields a coordinate system.

Study solves a generalized Christoffel-Minkowski problem using curvature flow.

problem Generalization of the LpL_{p}-Christoffel-Minkowski problem.
method Anisotropic curvature flow to derive long-time existence and smooth solutions.
result Existence of smooth solutions for c=1c=1 under certain initial data.

Study anisotropic flows without global terms and solve dual Orlicz Christoffel-Minkowski problems.

problem Anisotropic flows without global forcing terms and dual Orlicz Christoffel-Minkowski problems.
method Existence results for dual Orlicz Christoffel-Minkowski type problems via stationary solutions of anisotropic flows.
result Existence results for a class of dual Orlicz Christoffel-Minkowski type problems.

A geometric flow based in the Riemann-Christoffel curvature tensor that in two dimensions has some common features with the usual Ricci flow is presented. For nn dimensional spaces this new flow takes into account all the components of the intrinsic curvature. For four dimensional Lorentzian manifolds it is found that…

2007-07-02abs ↗pdf ↗

Solves Christoffel-Minkowski problem for capillary convex bodies in Euclidean half-space.

problem Finding capillary convex bodies with prescribed kk-th capillary area measure.
method Solving a Hessian-type equation with Robin boundary condition.
result Existence and uniqueness of a smooth solution under natural conditions.

Solves Christoffel-Minkowski problem and Hessian equations with radial symmetry.

problem Christoffel-Minkowski problem and Hessian equations under rotational symmetries.
method Constructing explicit convex solutions to mixed Monge-Ampère equations on \(\mathbb{R}^n\) under radial symmetry.
result Explicit representation formula for the support function of the resulting convex body.

Unified flow solves LpL^p Christoffel-Minkowski problem for p>1p>1.

problem Solving the LpL^p Christoffel-Minkowski problem for p>1p>1.
method Anisotropic expanding flow of smooth hypersurfaces with speed ψσk(λ)αψσ_k(λ)^α.
result The flow converges to a solution of the LpL^p Christoffel-Minkowski problem.

Weyl and Cartan proposed different but related ways to handle infinitesimal geometry in the early 1920s.

problem How to apply transformation groups in differential geometry.
method Both used connections and parallel transfer, with Cartan aiming for a more general framework.
result They reached an agreement on handling Cartan's infinitesimal geometric structures by the 1930s.

Log-concave coefficient sequences for two-bridge knots proved.

problem Proving log-concavity of Alexander polynomial coefficient sequences for alternating knots.
method Introducing a polynomial Δ(t)Δ(t) associated to Christoffel words and proving its log-concavity.
result Strong Fox conjecture for two-bridge knots proved.

Solves Christoffel-Minkowski problem for axially symmetric bodies.

problem Necessary and sufficient conditions for mixed area measures of axially symmetric convex bodies.
method Introduced a new method to transform mixed area measures and mixed volumes of axially symmetric bodies, refining Firey's classification and improving estimates.
result Complete solution to the mixed Christoffel-Minkowski problem for axially symmetric bodies without regularity assumptions.

Paper solves a geometric problem involving mixtures of area and curvature measures.

problem Investigates a geometric problem involving mixtures of area and curvature measures.
method Establishes a gradient estimate to prove the existence of a solution.
result Proves the existence of an even, smooth, strictly convex solution for 1<p<qk+11 < p < q \leq k + 1.

Paper studies inverse curvature flows and solves related geometric problems.

problem Inverse curvature flows and related geometric problems.
method Analyzes a class of expanding flows with specific speeds and proves existence and convergence.
result Proves the existence and convergence of flows under certain conditions, leading to new solutions to geometric problems.

It is shown that for small, spherically symmetric perturbations of asymptotically flat two-ended Reissner-Nordström data for the Einstein-Maxwell-real scalar field system, the boundary of the dynamic spacetime which evolves is globally represented by a bifurcate null hypersurface across which the metric extends continu…

2012-01-09abs ↗pdf ↗

The space of polygons up to similarity is studied using the Schwarz-Christoffel formula.

problem Understanding the space of polygons up to similarity.
method Using the Schwarz-Christoffel formula to show homeomorphism and proving embeddings for specific polygons.
result The space of labelled simple polygons up to similarity is homeomorphic to R^(2n-4) for n=3,4,5.

This paper optimizes sampling for least-squares approximation.

problem Optimizing sampling for least-squares approximation in arbitrary linear spaces.
method Introducing the Christoffel function to construct near-optimal random sampling strategies.
result The number of samples scales log-linearly in the dimension of the approximation space.

Outlier detection methods have become increasingly relevant in recent years due to increased security concerns and because of its vast application to different fields. Recently, Pauwels and Lasserre (2016) noticed that the sublevel sets of the inverse Christoffel function accurately depict the shape of a cloud of data …

2018-06-18abs ↗pdf ↗

We investigate the relation between quadrics and their Christoffel duals on the one hand, and certain zero mean curvature surfaces and their Gauss maps on the other hand. To study the relation between timelike minimal surfaces and the Christoffel duals of 1-sheeted hyperboloids we introduce para-holomorphic elliptic fu…

2017-01-09abs ↗pdf ↗