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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.

169,291 papers · 148 categories

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12.5%25.0%37.5%50.0% · Dec 199319922001200920182026
48 results for Reifenberg method

The article studies effective Reifenberg theorems in Hilbert and Banach spaces.

problem Understanding measures in Hilbert and Banach spaces.
method Analyzes Reifenberg theorems for measures in Hilbert and Banach spaces, providing conditions for rectifiability.
result Conditions for rectifiability of measures in Banach spaces, including a power gain for uniformly smooth spaces.

The paper extends regularity for pp-minimizing maps using a Reifenberg Theorem.

problem Quantitative regularity of pp-minimizing maps between Riemannian manifolds.
method Stratification of singular points based on almost-symmetries, followed by application of a Reifenberg-type Theorem.
result Upper bound on the Minkowski content of the singular set, and kk-rectifiability of the singular set.

This paper improves Reifenberg's theorem for almost calibrated sets, ensuring rectifiability with volume bounds.

problem Improving the rectifiability of sets that are close to subspaces under certain calibrations.
method Using ε-calibrations and positivity conditions, the paper shows that almost calibrated sets are rectifiable with volume bounds.
result Almost calibrated sets are rectifiable with uniform volume bounds.

Proof of Reifenberg theorem in metric spaces, expanding on Cheeger and Colding's work.

problem Proving the Reifenberg theorem in metric spaces using Gromov-Hausdorff distance.
method Detailed proof of Cheeger and Colding's result, expanding on their arguments.
result BiLipschitz version of the Reifenberg theorem in metric spaces.

The study defines a canonical nilpotent structure for certain collapsed manifolds.

problem Understanding the structure of collapsed Riemannian manifolds.
method Analyzes the nilpotent structure of manifolds with bounded Ricci curvature and Reifenberg local covering geometry.
result A canonical nilpotent structure can be defined and uniquely determined over regular limit spaces.

Harmonic maps to Euclidean buildings have rectifiable singular strata.

problem Understanding the structure of singular points for harmonic maps.
method Defining singular strata and proving rectifiability using the rectifiable Reifenberg program.
result Rectifiability of singular strata for harmonic maps into FF-connected complexes.

In this paper we study the regularity of stationary and minimizing harmonic maps f:B2(p)MNf:B_2(p)\subseteq M\to N between Riemannian manifolds. If $S^k(f)\equiv\{x\in M: \text{ no tangent map at $x$ is }k+1\text{-symmetric}\}$ is kthk^{th}-stratum of the singular set of ff, then it is well known that dimSkk\dim S^k\leq k, howeve…

2015-04-08abs ↗pdf ↗

In 1960 Reifenberg proved the topological disc property. He showed that a subset of RnR^n which is well approximated by mm-dimensional affine spaces at each point and at each (small) scale is locally a bi-Hölder image of the unit ball in RmR^m. In this paper we prove that a subset of R3R^3 which is well approximated b…

2006-07-18abs ↗pdf ↗

We study the existence and uniqueness of smooth mean curvature flow, in arbitrary dimension and co-dimension, emanating from so called kk-dimensional (ε,R)(\varepsilon,R) Reifenberg flat sets in Rn\mathbb{R}^n. Our results generalize the ones from a previous paper by the author, in which the co-dimension one case (i.e. $…

2015-08-13abs ↗pdf ↗

In this paper, we prove short time existence and uniqueness of smooth evolution by mean curvature in Rn+1\mathbb{R}^{n+1} starting from any nn-dimensional (ε,R)(\varepsilon,R)-Reifenberg flat set with ε\varepsilon sufficiently small. More precisely, we show that the level set flow in such a situation is non-fattening and …

2014-12-15abs ↗pdf ↗

We study here limit spaces (Mα,gα,pα)GH(Y,dY,p)(M_α,g_α,p_α)\stackrel{GH}{\rightarrow} (Y,d_Y,p), where the MαM_α have a lower Ricci curvature bound and are volume noncollapsed. Such limits YY may be quite singular, however it is known that there is a subset of full measure $\cR(Y)\subseteq Y$, called {\it regular} points, along with c…

2011-11-09abs ↗pdf ↗

Paper provides estimates for varifolds with critical mean curvature.

problem Estimating tilt-excess on varifolds with critical mean curvature.
method Generalizing Lipschitz approximation and Sobolev-Poincaré estimates to almost-integral rectifiable varifolds.
result VMO-type estimates for quadratic tilt-excess on varifolds with critical mean curvature.

The paper proves stability of Ricci flow for certain initial conditions.

problem Stability of Ricci flow for non-smooth initial metrics.
method Analyzes stability of Ricci flows starting from Reifenberg spaces with bounded curvature.
result Smooth three-dimensional, uniformly Ricci-pinched manifolds are either compact or flat.

Unified proof of smooth fibration theorems for collapsed manifolds.

problem Smooth fibration theorems for collapsed manifolds with Ricci curvature bounded below.
method Generalized Reifenberg condition and transformation technique for almost splitting maps.
result Unified proof of smooth fibration theorems in many previous works.

The paper proves fibration theorems for manifolds with almost nonnegative Ricci curvature.

problem Proving fibration theorems for manifolds with specific curvature conditions.
method Using equivariant regularity theorems and Gromov-Hausdorff convergence.
result Closed manifolds with certain curvature conditions fiber over a b1b_1-torus.

Study of collapsed manifolds with bounded Ricci curvature and non-collapsed universal cover.

problem Understanding collapsed manifolds with specific Ricci curvature properties.
method Ricci flow techniques applied to non-collapsed universal cover.
result Partial extension of nilpotent structural results to global Ricci bounded covering geometry.

Plateau's problem is to find a surface with minimal area spanning a given boundary. In 1960, Reifenberg and Adams developed a definition for "span" using Čech homology, and variants of this definition have been used ever sense. However, limitations of Čech homology resulted in the lack of a natural definition for a bou…

2014-12-06abs ↗pdf ↗

This paper studies limits of aspherical manifolds with specific curvature conditions.

problem Understanding the Gromov-Hausdorff limits of aspherical manifolds with given curvature constraints.
method Analyzing sequences of compact manifolds with Ricci curvature or sectional curvature conditions, and using diffeomorphism or homeomorphism properties.
result If the manifolds are diffeomorphic or homeomorphic to nilmanifolds, their limits are also diffeomorphic or homeomorphic to nilmanifolds.

A canonical diffeomorphism is constructed for manifolds near spheres.

problem Constructing a canonical diffeomorphism for manifolds near spheres.
method Using the first (n+1)(n+1)-eigenfunctions of the manifold, a map ildef ilde{f} is constructed and shown to be a diffeomorphism with a uniform bi-Hölder estimate.
result The constructed diffeomorphism ildef ilde{f} is canonical and satisfies a uniform bi-Hölder estimate, which is sharp and cannot be improved to a bi-Lipschitz estimate.

Study Ricci flows on manifolds, proving they behave like self-similar solutions and confirming a conjecture.

problem Understanding the behavior of Ricci flows on higher-dimensional manifolds.
method Analyzing nn-dimensional Ricci flows with non-negative Ricci curvature, starting at metric cones.
result Ricci flows behave like self-similar solutions up to an exponential error in time.

New epiperimetric inequality for cones with improved regularity results.

problem Regularity of almost area-minimizing currents at singular points.
method Flowing in radial direction for cones with isolated singularities.
result New ε-regularity result for almost area-minimizing currents.

The paper proves a transformation theorem under a monotone property of almost Euclidean factors of geodesic balls.

problem The non-increasing property of numbers of almost Euclidean factors of geodesic balls.
method Proves a transformation theorem under a non-decreasing property compared to the non-increasing property.
result Shows that for a manifold with nonnegative Ricci curvature, if its universal cover is polar at infinity and the number of almost Euclidean factors is monotone, then its fundamental group is finitely generated and virtually abelian.

A mean curvature flow starting from a closed embedded hypersurface in Rn+1R^{n+1} must develop singularities. We show that if the flow has only generic singularities, then the space-time singular set is contained in finitely many compact embedded (n1)(n-1)-dimensional Lipschitz submanifolds plus a set of dimension at most …

2014-05-20abs ↗pdf ↗

The paper proves topological stability between RCD spaces and Riemannian manifolds.

problem Proving topological stability between RCD spaces and Riemannian manifolds.
method Using Gromov-Hausdorff distance and regular homeomorphisms, the paper constructs a map between spaces.
result There exists a regular homeomorphism between RCD spaces and Riemannian manifolds under certain conditions.

New non-canonical flows found via parabolic Allen-Cahn equations.

problem Existence of non-canonical mean curvature flows inside fattening regions.
method Construction of non-canonical flows as limits of parabolic ε-Allen-Cahn solutions.
result First examples of non-outermost, non-canonical integral Brakke motions.

If one considers an integral varifold ImMI^m\subseteq M with bounded mean curvature, and if $S^k(I)\equiv\{x\in M: \text{ no tangent cone at $x$ is }k+1\text{-symmetric}\}$ is the standard stratification of the singular set, then it is well known that dimSkk\dim S^k\leq k. In complete generality nothing else is known about …

2015-04-27abs ↗pdf ↗

We describe a novel optimization method for finite sums (such as empirical risk minimization problems) building on the recently introduced SAGA method. Our method achieves an accelerated convergence rate on strongly convex smooth problems. Our method has only one parameter (a step size), and is radically simpler than o…

2016-02-08abs ↗pdf ↗

A new method combines Laplace and Variational Bayes for scalable inference.

problem Complex models and large datasets make exact inference infeasible.
method Low-Rank Variational Bayes Correction (VBC) using Laplace method and Variational Bayes correction in a lower dimension.
result The method ensures scalability in both model complexity and data size.

In this paper, the author considers the numerical computation of CVA for large systems by Mote Carlo methods. He introduces two types of stochastic mesh methods for the computations of CVA. In the first method, stochastic mesh method is used to obtain the future value of the derivative contracts. In the second method, …

2015-10-15abs ↗pdf ↗

Develops a fast method for pricing American options under variance gamma model.

problem Inefficient methods for pricing American options under variance gamma model.
method Inspired by quadratic approximation method, uses machine learning on pre-calculated quantities to reduce error.
result Proposed method is efficient and accurate for practical use.

Two RBF methods solve complex financial derivatives pricing problems.

problem Pricing derivatives in models with multiple stochastic factors.
method Radial Basis Function Partition of Unity and Radial Basis Function generated Finite Differences methods.
result Both methods achieve high accuracy and are efficient for solving multi-dimensional PDEs.

Simple stochastic Newton and cubic Newton methods with fast convergence.

problem Minimizing large numbers of smooth and strongly convex functions.
method Stochastic Newton and cubic Newton methods with simple local linear-quadratic rates.
result Local linear-quadratic convergence results with fast adaptation to problem's curvature.

Improved spectral methods of moments for robust latent variable model learning.

problem Limited robustness of spectral methods of moments to model misspecification.
method Hierarchical approach using approximate joint diagonalization instead of tensor decomposition.
result Our method outperforms previous tensor decomposition methods in speed and model quality.