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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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140280419559 · Jun 202019922001200920172026
48 results for approximation theory

The paper defines approximate fibrations in higher topos theory.

problem Defining approximate fibrations in a new mathematical framework.
method Introducing approximate fibrations for geometric morphisms of \infty-topoi, providing characterizations and comparing to previous definitions.
result Generalization of shape-theoretic characterizations to a topos-theoretical proof.

Theory for deep neural network approximation of score function and its derivatives.

problem Handling data distributions with low-dimensional structure and unbounded support.
method Simultaneous approximation of the score function and its derivatives using deep neural networks.
result Approximation error bounds match literature but relax bounded support requirement.

Deep, wide ConvResNets can approximate functions and their smoothness.

problem Function approximation and smoothness in deep networks.
method Analyzing ConvResNets, proving their ability to approximate functions and their smoothness.
result Large ConvResNets can approximate functions and exhibit sufficient first-order smoothness.

We study sparse approximate solutions to convex optimization problems. It is known that in many engineering applications researchers are interested in an approximate solution of an optimization problem as a linear combination of elements from a given system of elements. There is an increasing interest in building such …

2012-06-02abs ↗pdf ↗

Unified theory for semi-implicit variational inference, bridging approximation and optimization.

problem Developing a statistical theory for semi-implicit variational inference.
method Unified theory combining approximation and optimization analyses.
result Unified theory characterizes SIVI's ability to recover target distributions and governs asymptotic behavior.

We build on the dynamical systems approach to deep learning, where deep residual networks are idealized as continuous-time dynamical systems, from the approximation perspective. In particular, we establish general sufficient conditions for universal approximation using continuous-time deep residual networks, which can …

2019-12-22abs ↗pdf ↗

Develops wavelet-based neural network approximation theory.

problem Analyzing neural network approximation capabilities over various activation functions.
method Wavelet frame theory on spaces of homogeneous type, sufficient conditions for approximation, error estimates.
result Derives sufficient conditions for neural networks to approximate any functions in a given space, including non-smooth activations.

This research develops approximation theory for OOMs of infinite-dimensional processes.

problem Developing an approximation theory for OOMs of infinite-dimensional processes.
method Establishing an inner product structure and proving continuity of observable operators.
result A fundamental obstacle in making an infinite-dimensional space of future distributions into a Hilbert space is described.

The paper develops AMP theory for sparse and robust regression with polynomial iterations.

problem Challenges in high-dimensional statistical estimation due to asymptotic theory breakdown.
method Non-asymptotic distributional theory of AMP for sparse and robust regression.
result First finite-sample non-asymptotic distributional theory of AMP for polynomial iterations.

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.

Improved neural network approximates analytic and L^p functions efficiently.

problem Efficiently approximating analytic and L^p functions using neural networks.
method Three-dimensional ReLU network architecture for sawtooth functions, improving approximation rates.
result Substantially improved exponential approximation rates for analytic functions and general L^p functions.

New findings on how convolutional architectures approximate time series data.

problem Understanding the approximation properties of convolutional architectures in time series modeling.
method Mathematical analysis of convolutional architectures applied to time series modeling.
result A new definition of spectrum-based regularity for measuring temporal relationships under convolutional approximation.

Study variation spaces for neural networks, linking them to approximation theory.

problem Understanding the variation spaces of shallow neural networks.
method Examined variation spaces defined by convex hulls and integral representations for a dictionary of functions.
result Found that Barron space, spectral Barron space, and Radon BV space are variation spaces for certain neural networks.

Transformers enable in-context learning with guarantees for a wide range of tasks.

problem How to enable in-context learning with transformers for various tasks.
method Developed a universal approximation theory integrating Barron's function approximation with transformer capabilities.
result Transformers can approximate any target function with vanishingly small risk using a few in-context examples.

Deep residual networks can approximate any continuous function using control theory.

problem Universal approximation capabilities of deep residual neural networks.
method Relating residual networks to control systems and using Lie algebraic techniques.
result Deep residual networks with adequately deep layers can approximate any continuous function on a compact set.

Gradient descent trains shallow neural networks to approximate functions in 1D.

problem Approximating functions in 1D with shallow neural networks trained by gradient descent.
method Gradient descent optimization of non-convex weight space for finite width networks in 1D.
result Gradient descent can approximate functions in 1D with a minimal number of weights, balancing practical performance and theoretical capabilities.

FQE with deep neural networks achieves asymptotic normality and finite-sample bounds.

problem Theoretical understanding of FQE with general differentiable function approximators.
method Z-estimation theory applied to FQE with deep neural networks.
result FQE estimation error is asymptotically normal with explicit variance.

Study approximates top Lyapunov exponents for surface mapping classes.

problem Approximating topological Lyapunov exponents for surface mapping classes.
method Periodic approximation and joint spectral radius extension.
result Top Lyapunov exponents can be approximated by periodic orbits.

Survey discusses new ideas in geometric group theory and their applications.

problem Understanding geodesic metric spaces and their equivariant wall structures.
method Introduces and highlights the impact of injective metric spaces and cubical approximation theorem.
result Rich equivariant wall structures in various geodesic metric spaces.

Almost perimeter-minimizing boundaries in plentiful groups can be approximated by Lipschitz graphs.

problem Regularity of boundaries in plentiful groups.
method Lipschitz approximation of boundaries.
result Boundary of almost minimizers can be approximated by intrinsic Lipschitz graphs.

We study the Stochastic Gradient Descent (SGD) method in nonconvex optimization problems from the point of view of approximating diffusion processes. We prove rigorously that the diffusion process can approximate the SGD algorithm weakly using the weak form of master equation for probability evolution. In the small ste…

2017-05-22abs ↗pdf ↗

Paper studies Transformer learning theory for Euclidean and Riemannian domains.

problem Understanding and optimizing Transformer networks for regression tasks.
method Constructive approximation framework using softmax partition of unity and attention mechanism.
result Transformer can achieve uniform ε-approximation error with minimal parameters.

We extend the Eliashberg-Thurston theorem on approximations of taut oriented C2C^2-foliations of 3-manifolds by both positive and negative contact structures to a large class of taut oriented C1,0C^{1,0}-foliations, where by C1,0C^{1,0} foliation, we mean a foliation with continuous tangent plane field. These C1,0C^{1,0}-fol…

2014-04-20abs ↗pdf ↗

Zap Q-learning is a recent class of reinforcement learning algorithms, motivated primarily as a means to accelerate convergence. Stability theory has been absent outside of two restrictive classes: the tabular setting, and optimal stopping. This paper introduces a new framework for analysis of a more general class of r…

2019-10-11abs ↗pdf ↗

New theory approximates functions between metric spaces using random probability measures.

problem Building universal functions approximators between arbitrary metric spaces.
method Using elementary functions between Euclidean spaces, randomization to output discrete probability measures over target space.
result Very general qualitative guarantees and quantitative guarantees for Hölder-like maps.

Survey on statistical theories of neural networks, focusing on approximation, training dynamics, and generative models.

problem Understanding the statistical properties and training dynamics of neural networks.
method Review of existing literature on neural networks from three perspectives: approximation, training dynamics, and generative models.
result Theoretical insights into neural network training dynamics and generative models.

New framework connects two neural network theories, improving finite-width approximations.

problem Theoretical guarantees for neural network training in general cases.
method Developed a general framework linking mean-field and constant kernel theories.
result Discrete-time MF limit provides better approximation for finite-width nets.

Paper develops approximation and statistical theory for signature-based path regression.

problem Understanding how fast signatures approximate continuous path functionals.
method Develops \(L^2\) approximation rate for smooth functionals of Itô diffusions and establishes consistency of statistical learning procedures.
result Signature-based methods improve prediction over handcrafted features in various real-data applications.

Neural networks approximate high-dimensional functions better than theory predicts.

problem Current theory struggles to explain why small neural networks work well in high-dimensional inverse problems.
method Bounding complexity required for neural networks to approximate Hölder or uniformly continuous functions on high-dimensional sets.
result A general theoretical framework explaining empirical successes of smaller networks in inverse problems.

Paper develops efficient RL algorithm for general value function approximation.

problem Lack of theory for RL with general value function approximation.
method Provable efficient RL algorithm using bounded eluder dimension.
result Achieves a regret bound of O~(poly(dH)T)\widetilde{O}(\mathrm{poly}(dH)\sqrt{T}).

This paper develops fundamental limits of deep neural network learning by characterizing what is possible if no constraints are imposed on the learning algorithm and on the amount of training data. Concretely, we consider Kolmogorov-optimal approximation through deep neural networks with the guiding theme being a relat…

2019-01-08abs ↗pdf ↗