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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.

168,695 papers · 148 categories

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82164245327 · Jun 202019922001200920172026
48 results for essential regularity

Study submanifolds in hyperbolic space, focusing on their boundary and Laplace operator.

problem Understanding the geometry and regularity of submanifolds in hyperbolic space.
method Analyzing asymptotic geometry and regularity properties near the ideal boundary, computing essential spectra.
result Computed essential spectra of the Laplace operator on certain submanifolds.

We prove a general essential self-adjointness criterion for sub-Laplacians on complete sub-Riemannian manifolds, defined with respect to singular measures. As a consequence, we show that the intrinsic sub-Laplacian (i.e. defined w.r.t. Popp's measure) is essentially self-adjoint on the equiregular connected components …

2017-08-31abs ↗pdf ↗

Constructs geometries with nonvanishing curvature and essential automorphisms.

problem Creating geometries with nonvanishing curvature and essential automorphisms.
method Using elements of the kernel of the Kostant Laplacian to construct homogeneous Cartan geometries, then modifying them to make base manifolds compact.
result Infinite families of regular normal Cartan geometries with nonvanishing curvature and essential automorphisms on closed manifolds for higher rank parabolic model geometries.

We prove that the essential smoothness of the gravitational metric at shock waves in GR, a PDE regularity issue for weak solutions of the Einstein equations, is determined by a geometrical condition which we introduce and name the {\it Riemann-flat condition}. The Riemann-flat condition determines whether or not the es…

2016-10-07abs ↗pdf ↗

New methods improve estimation of nonhomogeneous Poisson processes from limited data.

problem Estimating nonhomogeneous Poisson processes from limited data.
method Formulated as a learning generalization problem, proposed adaptive and data-driven binning methods.
result Improved estimation of nonhomogeneous Poisson processes with limited data.

Given a closed submanifold, or a compact regular domain, in euclidean space, we consider the Riesz energy defined as the double integral of some power of the distance between pairs of points. When this integral diverges, we compare two different regularization techniques (Hadamard's finite part and analytic continuatio…

2015-12-25abs ↗pdf ↗

We study the spectrum of the Finsler--Laplace operator for regular Hilbert geometries, defined by convex sets with C2C^2 boundaries. We show that for an nn-dimensional geometry, the spectral gap is bounded above by (n1)2/4(n-1)^2/4, which we prove to be the infimum of the essential spectrum. We also construct examples of c…

2012-11-27abs ↗pdf ↗

Efficient methods for Lévy models using SINH-regular processes.

problem Efficient numerical methods for evaluating Lévy models.
method Defining SL-processes and sSL-processes, deriving properties of characteristic exponent, and showing all popular Lévy processes can be subordinated to Brownian motion.
result All crucial properties of characteristic exponent are consequences of a specific representation, and all popular Lévy processes are SL- or sSL-subordinated Brownian motion.

In this paper, we study some intrinsic characterization of conformally compact manifolds. We show that, if a complete Riemannian manifold admits an essential set and its curvature tends to -1 at infinity in certain rate, then it is conformally compactifiable and the compactified metrics can enjoy some regularity at inf…

2009-10-12abs ↗pdf ↗

Generalization is essential for deep learning. In contrast to previous works claiming that Deep Neural Networks (DNNs) have an implicit regularization implemented by the stochastic gradient descent, we demonstrate explicitly Bayesian regularizations in a specific category of DNNs, i.e., Convolutional Neural Networks (C…

2019-10-22abs ↗pdf ↗

In text classification, the problem of overfitting arises due to the high dimensionality, making regularization essential. Although classic regularizers provide sparsity, they fail to return highly accurate models. On the contrary, state-of-the-art group-lasso regularizers provide better results at the expense of low s…

2018-07-12abs ↗pdf ↗

The paper studies properties of RCD(K,N)\mathrm{RCD}(K,N) spaces and their boundaries.

problem Understanding the boundary structure and unit normal on RCD(K,N)\mathrm{RCD}(K,N) spaces.
method Proves concentration of boundary measure, discusses localization of unit normal, and develops tools for perimeter minimizers.
result Proves that the boundary measure of sets with finite perimeter is concentrated on the nn-regular set Rn\mathcal{R}_n.

Deep neural networks achieve optimal learning rates for high-dimensional classification.

problem Learning classification functions from noisy data with smooth boundaries.
method Empirical risk minimization over deep neural networks for locally Barron-regular decision boundaries.
result Optimal estimation rates are independent of dimension and can be achieved by deep neural networks.

Study shows nonexistence of certain geometric structures in complex geometries.

problem Failure of Lichnerowicz-type conjectures in specific parabolic geometries.
method Used techniques from Erickson to establish existence of specific geometries.
result Nonexistence of certain geometric structures in Yamaguchi nonrigid parabolic models.

Regularization is essential when training large neural networks. As deep neural networks can be mathematically interpreted as universal function approximators, they are effective at memorizing sampling noise in the training data. This results in poor generalization to unseen data. Therefore, it is no surprise that a ne…

2014-12-20abs ↗pdf ↗

It is shown that the geodesic rays constructed as limits of Bergman geodesics from a test configuration are always of class C1,α,0<α<1C^{1,α}, 0<α<1. An essential step is to establish that the rays can be extended as solutions of a Dirichlet problem for a Monge-Ampere equation on a Kaehler manifold which is compact.

2009-08-04abs ↗pdf ↗

The paper uses machine learning to forecast macroeconomic outcomes with high-dimensional data.

problem Forecasting the full conditional distribution of macroeconomic outcomes.
method Systematically integrating three key principles: high-dimensional data with regularization, rigorous out-of-sample validation, and incorporating nonlinearities.
result Regularization via shrinkage is essential to control model complexity, while nonlinearities yield limited improvements in predictive accuracy.

We propose an inference method to estimate sparse interactions and biases according to Boltzmann machine learning. The basis of this method is L1L_1 regularization, which is often used in compressed sensing, a technique for reconstructing sparse input signals from undersampled outputs. L1L_1 regularization impedes the …

2015-03-11abs ↗pdf ↗

Researchers extend regularity of pp-harmonic maps into spheres for a new range of pp.

problem Establishing regularity of pp-harmonic maps for a broader range of pp.
method Combining Morrey's methods with Hardt and Lin's Extension Theorem, and proving a sharp Kato inequality.
result Regularity for p[2.961,3]p \in [2.961, 3] and p[2,p0]p \in [2, p_0] with p02.366p_0 \approx 2.366.

Study Brownian loops on hyperbolic surfaces, linking to Selberg zeta function.

problem Understanding Brownian loops on hyperbolic surfaces and their relation to Selberg zeta function.
method Computed mass of loops and related to Selberg zeta function for geometrically finite surfaces.
result Relate total loop mass to Selberg zeta function, providing probabilistic interpretations of determinants.

A new method for VAEs improves latent space disentanglement without violating probability laws.

problem Improving latent space disentanglement in VAEs without violating probability laws.
method Developed a Renyi VAE with a conditional distribution not learned, using Singular Value Decomposition for evaluation.
result Improved latent space disentanglement without violating probability laws.

Supervised learning alone can be effective for offline RL, revealing essential elements.

problem Understanding when and how supervised learning alone can be effective for offline RL.
method Extensive experiments to identify essential elements for offline RL via supervised learning.
result Maximizing likelihood with a two-layer feedforward MLP is competitive with more complex methods.

Recommendation models mainly deal with categorical variables, such as user/item ID and attributes. Besides the high-cardinality issue, the interactions among such categorical variables are usually long-tailed, with the head made up of highly frequent values and a long tail of rare ones. This phenomenon results in the d…

2019-05-28abs ↗pdf ↗

Ablation studies show BCF model's propensity score is not essential for treatment effect estimation.

problem Understanding the necessity of propensity score in nonparametric treatment effect estimation.
method Partial ablation studies of Bayesian Causal Forest (BCF) model.
result Excluding estimated propensity score does not affect treatment effect estimation or uncertainty quantification.

In this paper we study constant scalar curvature equation (CSCK), a nonlinear fourth order elliptic equation, and its weak solutions on Kähler manifolds. We first define a notion of weak solution of CSCK for an LL^\infty Kähler metric. The main result is to show that such a weak solution (with uniform LL^\infty bound…

2017-05-03abs ↗pdf ↗

An essentially unique homeomorphic solution to the Beltrami equation was found in the 1960s using the theory of Calderón-Zygmund and singular integral operators in Lp(C)L^p(\mathbb C). We will present an alternative method to solve the Beltrami equation using the Hodge star operator and standard elliptic PDE theory. We wi…

2018-01-24abs ↗pdf ↗

The general theory of boundary value problems for linear elliptic wedge operators (on smooth manifolds with boundary) leads naturally, even in the scalar case, to the need to consider vector bundles over the boundary together with general smooth fiberwise multiplicative group actions. These actions, essentially trivial…

2013-01-24abs ↗pdf ↗