New method constructs holonomic immersions from flat submanifolds.
problem Creating holonomic immersions from flat submanifolds.
method Ribaucour transformation and principal coordinate system.
result Holonomic immersions can be constructed using Ribaucour transformation.
Study on conformal harmonic coordinates on manifolds, proving existence and properties.
problem Existence and properties of conformal harmonic coordinates on Riemannian manifolds.
method Solutions to the conformal Laplace equation, proving up to boundary regularity results, elliptic regularity, and unique continuation results.
result Proves conformal harmonic coordinates are a close conformal analogue of harmonic coordinates.
This paper constructs a family of coordinate systems about a point on a quaternionic contact manifold, called quaternionic contact pseudohermitian normal coordinates. Once defined, conformal variations of the quaternionic contact structure induce changes on the coordinates which are studied in an effort to simplify the…
Analytic plane curves determine unique conformal coordinates.
problem Determining a conformal coordinate system for analytic plane curves.
method Holomorphic continuation of the Frenet curvature form.
result Holomorphic continuation of the curvature form uniquely determines a conformal coordinate net.
In many problems of PDE involving the Laplace-Beltrami operator on manifolds with ends, it is often useful to introduce radial or geodesic normal coordinates near infinity. In this paper, we prove the existence of such coordinates for a general class of manifolds with ends, which contains asymptotically conical and hyp…
In this article we introduce local gauge conditions under which many curvature tensors appearing in conformal geometry, such as the Weyl, Cotton, Bach, and Fefferman-Graham obstruction tensors, become elliptic operators. The gauge conditions amount to fixing an n-harmonic coordinate system and normalizing the determi…
New findings on Kähler manifolds restrict orthogonal coordinates existence.
problem Existence of orthogonal coordinates on Kähler manifolds.
method Algebraic and geometric techniques applied to Kähler manifolds.
result No nontrivial self-dual Kähler 4-manifolds or Ricci-flat Kähler 4-manifolds support orthogonal coordinates.
Study of sixth order GJMS operator on Einstein manifolds.
problem Analysis of sixth order GJMS operator and its applications.
method Expansion of Green's function in conformal normal coordinates, existence results for prescribed Q-curvature problem.
result Existence of conformal metrics with prescribed sixth order Q-curvature on Einstein manifolds.
New tractor geometry derived from asymptotically flat spacetimes.
problem Understanding the geometry of spacetimes near their boundaries.
method Derived null-tractor bundle from interior spacetime geometry, proved connections' uniqueness, and expressed results in BMS coordinates.
result Tractor connection encodes mass and angular momentum in 3D, and asymptotic shear in higher dimensions.
This study recovers electromagnetic parameters on boundaries from impedance and admittance data.
problem Recovering anisotropic electromagnetic parameters from boundary impedance and admittance data.
method Formulated inverse boundary value problem for time-harmonic Maxwell's equations on differential 1-forms.
result Knowledge of impedance and admittance maps determines tangential entries of induced metrics at the boundary.
LOCA learns standardized data coordinates from measurements.
problem Learning invariant data coordinates from non-linearly deformed manifolds.
method LOCA, a LOcal Conformal Autoencoder, learns an isometric embedding.
result LOCA preserves geometric information while learning invariant coordinates.
Normalizes pseudo-Einstein contact forms for easier analysis.
problem Understanding pseudo-Einstein contact forms.
method Constructing intrinsic CR normal coordinates using parabolic normal coordinates.
result Normal form for pseudo-Einstein contact forms.
This article studies the smoothness of conformal mappings between two Riemannian manifolds whose metric tensors have limited regularity. We show that any bi-Lipschitz conformal mapping or 1-quasiregular mapping between two manifolds with Cr metric tensors (r>1) is a Cr+1 conformal (local) diffeomorphism. …
Monotonicity of normalized implied-volatility coordinates under no-arbitrage
problem Monotonicity of normalized implied-volatility coordinates under no-arbitrage
method Elementary discrete no-arbitrage proof
result Monotonicity principle extended to Bachelier implied volatility
The study compares Kähler and Riemannian normal coordinates on manifolds.
problem Understanding the differences and similarities between Kähler and Riemannian normal coordinates.
method Developed an algorithm to calculate the difference between Kähler and Riemannian normal coordinates as a universal power series in curvature tensor and its derivatives.
result The difference between Kähler and Riemannian normal coordinates is a universal power series in curvature tensor and its derivatives.
Paper classifies rational 3-tangles using normal forms and minimal coordinates.
problem Classifying rational 3-tangles up to isotopy.
method Defined normal form and normal coordinate, investigated minimal coordinates, constructed contractible simplicial complex.
result Simplicial complex of normal forms is contractible, leading to classification of rational 3-tangles.
Study of Demoulin surfaces using Gauss maps and conformal coordinates.
problem Characterizing Demoulin surfaces in real projective 3-space.
method Generalized Weierstrass type representation via primitive maps.
result Established a new representation for Demoulin surfaces.
In p-harmonic coordinates, Hölder metrics lead to useful gauge conditions in conformal geometry.
problem Establishing useful gauge conditions for regularity in conformal geometry.
method Development of p-harmonic coordinates on Riemannian manifolds with Hölder continuous metrics.
result Conformal mappings between manifolds with Hölder metrics are C1+α regular. Normal and almost normal surfaces are essential tools for algorithmic 3-manifold topology, but to use them requires exponentially slow enumeration algorithms in a high-dimensional vector space. The quadrilateral coordinates of Tollefson alleviate this problem considerably for normal surfaces, by reducing the dimension …
Researchers find Fenchel-Nielsen coordinates for asymptotically conformal maps on hyperbolic surfaces.
problem Parametrizing the space of asymptotically conformal maps on hyperbolic surfaces.
method Using Fenchel-Nielsen coordinates, the researchers find parametrizations of the little Teichmüller space and its closure in the length spectrum metric.
result The quotients of Teichmüller spaces are contractible, and Wolpert's lemma on geodesic lengths is not sharp.
Paper proposes efficient training for normalizing flows in Boltzmann generators.
problem Training normalizing flows for Boltzmann generators is computationally challenging and unstable.
method Regression Training of Normalizing Flows (RegFlow) using ℓ2-regression. result RegFlow enables efficient and stable training of normalizing flows for Boltzmann generators.
We derive an integral representation which encodes all coefficients of the Riemann normal coordinate expansion, and also a closed formula for those coefficients.
Elie Cartan's general equivalence problem is recast in the language of Lie algebroids. The resulting formalism, being coordinate and model-free, allows for a full geometric interpretation of Cartan's method of equivalence via reduction and prolongation. We show how to construct certain normal forms (Cartan algebroids) …
Researchers solve a complex problem about determining Riemannian manifolds.
problem Determine the conformal class of a Riemannian manifold with boundary from the Dirichlet-to-Neumann map.
method Uses conformal invariance and introduces a new coordinate system to solve the problem on a real-analytic Riemannian manifold.
result Locally conformally real-analytic manifolds in dimensions ≥ 3 can be determined from the Dirichlet-to-Neumann map.
We introduce in this paper normal twistor equations for differential forms and study their solutions, the so-called normal conformal Killing forms. The twistor equations arise naturally from the canonical normal Cartan connection of conformal geometry. Reductions of its holonomy are related to solutions of the normal t…
Study on 3-manifolds finds regular conformal metrics for rough metrics.
problem Characterize conformal metrics for rough Riemannian metrics on 3-manifolds.
method Analogous to the Yamabe problem, study conformal classes and regularity.
result Characterize when a more regular representative exists in the conformal class.
The theory of frames normal for general connections on differentiable bundles is developed. Links with the existing theory of frames normal for covariant derivative operators (linear connections) in vector bundles are revealed. The existence of bundle coordinates normal at a given point and/or along injective horizonta…
New theorem proves convergence of various discrete conformal structures to conformal maps.
problem Proving convergence of discrete conformal structures to conformal maps.
method General theorem using piecewise linear discrete conformal mappings and Riemannian barycentric coordinates.
result Discrete conformal mappings converge to conformal maps under certain conditions.
J. Nitsche's theorem on conformal hyperbolic metrics is extended with new expressions for metrics near isolated singularities.
problem Characterizing isolated singularities of conformal hyperbolic metrics.
method Developing a complex coordinate map to analyze the metric near the singularity.
result New expressions for conformal hyperbolic metrics near isolated singularities are derived.
The main subject of the book is an up-to-date and in-depth survey of the theory of normal frames and coordinates in differential geometry. The book can be used as a reference manual, review of the existing results and introduction to some new ideas and developments. In the book can be found practically all existing ess…
We construct a tangent bundle exponential map and locally autoparallel coordinates for geometries based on a general connection on the tangent bundle of a manifold. As concrete application we use these new coordinates for Finslerian geometries and obtain Finslerian geodesic coordinates. They generalise normal coordinat…
The paper examines flatness conditions on normal metric contact pairs and proves properties of Einstein manifolds.
problem The study of flatness conditions on normal metric contact pairs.
method Analysis of conformal, concircular, and quasi-conformal curvature tensors.
result Normal metric contact pair manifolds with flat conformal, concircular, and quasi-conformal curvature tensors are Einstein manifolds with specific scalar and sectional curvatures.
Equivalence of conformal maps proved in sub-Riemannian manifolds.
problem Equivalence of conformal maps between sub-Riemannian manifolds.
method Regularity theory for subelliptic p-Laplacian operators, sub-Riemannian p-harmonic coordinates, propagation of regularity.
result 1-quasiconformal maps are smooth on contact manifolds.
Locally symplectic structure found on Kerr space-time.
problem Understanding Kerr space-time using geodesics.
method Identifying locally conformally symplectic structure using characteristic classes and Kerr-Schild coordinates.
result Definition of cobordism category of contact 3-manifolds and locally conformally symplectic cobordisms.
Contact Riemannian manifolds, whose complex structures are not necessarily integrable, are generalization of pseudohermitian manifolds in CR geometry. The Tanaka-Webster-Tanno connection plays the role of the Tanaka-Webster connection of a pseudohermitian manifold. Conformal transformations and the Yamabe problem are a…
The enumeration of normal surfaces is a crucial but very slow operation in algorithmic 3-manifold topology. At the heart of this operation is a polytope vertex enumeration in a high-dimensional space (standard coordinates). Tollefson's Q-theory speeds up this operation by using a much smaller space (quadrilateral coord…
Consider a smooth manifold M with a smooth cometric g∗ which changes the bilineal type by transverse way, on a hypersurface D∞. Suppose that the radical annihilator hyperplane is tangent to D∞. We examine the geometry of the (g∗-dual) covariant metric g on M− D∞, prov…
New relation found between ambient obstruction tensor and conformal holonomy.
problem Understanding the properties of conformal structures and their holonomy.
method Introducing the conformal holonomy distribution and proving its integrability.
result Proves several results on the vanishing and rank of the obstruction tensor.
Defines natural tensors for submanifolds of pseudo-Riemannian manifolds.
problem Characterizing tensors for submanifolds of pseudo-Riemannian manifolds.
method Constructs geodesic normal coordinates and expresses metric coefficients as polynomials in curvature and second fundamental form derivatives.
result Natural tensors are linear combinations of contractions of curvature and second fundamental form derivatives.
In this paper, we investigate the behavior of the normalized Ricci flow on asymptotically hyperbolic manifolds. We show that the normalized Ricci flow exists globally and converges to an Einstein metric when starting from a non-degenerate and sufficiently Ricci pinched metric. More importantly we use maximum principles…
New Hermite approximations accelerate convergence with adaptive coordinate transformations.
problem Accelerating convergence of spectral approximations for Hermite expansions.
method Using normalizing flows for adaptive coordinate transformations and deriving error estimates.
result Error estimates for Hermite expansions under adaptive coordinate transformations.
A method constructs tractor conformal bundles for spacelike submanifolds in Lorentzian manifolds.
problem Characterize conditions for a tractor conformal bundle to be standard and normal.
method Introduce a canonical construction of a tractor conformal bundle and characterize conditions for it to be standard and normal.
result Characterizes conditions for a tractor conformal bundle to be standard and normal.
Study eigenvalues of conformal Laplacian under Sire-Xu normalization.
problem Existence and properties of extremal eigenvalues under a specific normalization.
method Variational analysis of eigenvalue functional under Sire-Xu normalization.
result Necessary conditions and existence results for extremal eigenvalues.
Paper finds local normal forms for wavefronts in flat coordinates.
problem Understanding local diffeomorphic types of wavefronts.
method Using connections and the metric, criteria for wavefront types are derived in affine flat coordinates.
result Local normal forms of e/m-wavefronts in affine flat coordinates are derived. A new proof shows how to characterize maps using simple geometry.
problem Characterizing quasisymmetric maps on the unit circle.
method Elementary proof using normal family argument and hyperbolic geometry.
result Characterizes quasisymmetric maps via shear coordinates on the Farey tesselation.
Canonical coordinates defined for minimal time-like surfaces in n-dimensional Minkowski space.
problem Characterizing canonical coordinates on minimal time-like surfaces.
method Introducing canonical coordinates and proving their existence and uniqueness; using analysis over the algebra of double numbers.
result Canonical coordinates on minimal time-like surfaces are characterized by a natural condition for a complex function over the algebra of double numbers.
The paper shows integrability of scalar curvature implies normal metric on conformally flat manifolds.
problem Integrability of scalar curvature and normal metric on conformally flat manifolds.
method Analyzes the Q-curvature equation and its integral form to show integrability implies normality. result Integrability of the negative part of scalar curvature implies the metric is normal.
Example shows no global coordinates on 2-torus's cover.
problem Existence of global coordinates on Riemannian metrics.
method Constructing a specific metric on a 2-torus.
result No global Riemann normal coordinates on the universal cover.