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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.

169,051 papers · 148 categories

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73145218290 · Jun 202019922001200920172026
48 results for slow rates

The paper derives oracle inequalities for estimators with fast and slow rates.

problem Developing fast and slow oracle inequalities for estimators.
method Direct study of analysis estimator and adaptation of Dalalyan, Hebiri and Lederer's arguments.
result Constant-friendly rates for (square root) total variation regularized estimators over graphs.

We consider the stochastic contextual bandit problem with additional regularization. The motivation comes from problems where the policy of the agent must be close to some baseline policy which is known to perform well on the task. To tackle this problem we use a nonparametric model and propose an algorithm splitting t…

2018-10-11abs ↗pdf ↗

Gradient descent slows significantly in over-parameterized single neuron learning.

problem Learning a single neuron with over-parameterization and square loss.
method Analysis of gradient descent dynamics, proving convergence rates and lower bounds.
result Over-parameterization can exponentially slow down the convergence rate of gradient descent.

EM algorithm converges slowly for weakly identifiable Gaussian mixtures.

problem Slow convergence of EM algorithm for weakly identifiable Gaussian mixtures.
method Localized argument with two stages, each involving epoch-based arguments for surrogate EM operators at the population level.
result EM algorithm converges in $n^{ rac{3}{4}}$ steps with estimates at Euclidean distance of $n^{- rac{1}{8}}$ and $n^{- rac{1}{4}}$ from true parameters.

In this paper we address the following question: Can we approximately sample from a Bayesian posterior distribution if we are only allowed to touch a small mini-batch of data-items for every sample we generate?. An algorithm based on the Langevin equation with stochastic gradients (SGLD) was previously proposed to solv…

2012-06-27abs ↗pdf ↗

We consider in a market model the cooperative emergence of value due to a positive feedback between perception of needs and demand. Here we consider also a negative feedback from production of the traded products, and find that this cooperativity is robust, provided that the production rate is slow. Cooperativity is fo…

2003-09-24abs ↗pdf ↗

When applied to training deep neural networks, stochastic gradient descent (SGD) often incurs steady progression phases, interrupted by catastrophic episodes in which loss and gradient norm explode. A possible mitigation of such events is to slow down the learning process. This paper presents a novel approach to contro…

2017-09-05abs ↗pdf ↗

The paper analyzes why Gaussianization slows down with higher dimensions and proposes a solution.

problem The convergence rate of Gaussianization slows down as the dimension increases.
method Analytical and empirical analysis of Gaussianization with random rotations.
result The number of required layers scales linearly with the dimension for Gaussian input.

Improved fast rates for decision making with forward-KL regularization in contextual bandits.

problem Improving fast rates for decision making with forward-KL regularization in contextual bandits.
method Streamlined analysis of forward-KL-regularized offline CBs, exploiting the pessimism principle and convex-analytical pipeline.
result First ildeO(ε1) ilde{O}(ε^{-1}) upper bounds in tabular and general function approximation settings.

We consider the action of a pseudo-Anosov mapping class on PML(S)\mathcal{PML}(S). This action has north-south dynamics and so, under iteration, laminations converge exponentially to the stable lamination. We study the rate of this convergence and give examples of families of pseudo-Anosov mapping classes where the rate go…

2015-12-02abs ↗pdf ↗

Empirical risk minimization (ERM) is a fundamental learning rule for statistical learning problems where the data is generated according to some unknown distribution P\mathsf{P} and returns a hypothesis ff chosen from a fixed class F\mathcal{F} with small loss \ell. In the parametric setting, depending upon $(\ell…

2014-06-14abs ↗pdf ↗

This article derives prognostic expressions for the evolution of globally aggregated economic wealth, productivity, inflation, technological change, innovation and growth. The approach is to treat civilization as an open, non-equilibrium thermodynamic system that dissipates energy and diffuses matter in order to sustai…

2013-06-15abs ↗pdf ↗

Paper analyzes convergence of FedAvg on non-iid data and provides theoretical guarantees.

problem Analyzing convergence of Federated Averaging on non-iid data.
method Theoretical analysis of convergence rate and trade-offs between communication-efficiency and convergence rate.
result Established a convergence rate of O(1T)\mathcal{O}(\frac{1}{T}) for strongly convex and smooth problems.

Study on slow convergence in geometric variational problems.

problem Slow convergence of solutions in geometric variational problems.
method Identifying necessary conditions for slowly converging solutions and characterizing their convergence rate and direction.
result Characterization of the rate and direction of convergence for slowly converging solutions.

The paper tackles long-context linear system identification with improved sample complexity bounds.

problem Identifying dynamical systems with long dependencies over fixed context windows.
method Established sample complexity bounds for systems with linear dependencies over a context window of length p.
result The learning process is not hindered by slow mixing properties in extended context windows.

The paper challenges the use of decision trees for pointwise inference due to slow convergence rates.

problem The slow convergence rates of decision trees in uniform norm, especially with non-vanishing probability.
method Demonstrates the limitations of adaptive recursive partitioning and shows how random forests can improve performance.
result Decision trees can fail to achieve polynomial rates of convergence in uniform norm, even with pruning.

Improved stochastic approximation method reduces residual error.

problem Reducing residual error in stochastic approximation algorithms.
method Fixed-schedule one-quarter barrier and bias-corrected acceleration.
result Achieves T1/2+o(1)T^{-1/2+o(1)} residual reduction with O(1)O(1) primitive samples.

Efficiently simulates slow dynamics of high-dimensional stochastic systems.

problem Simulating high-dimensional stochastic systems with slow dynamics and fast modes.
method Designs an algorithm to estimate an invariant manifold and its dynamics, averaging out fast modes.
result Efficient simulator of effective dynamics on low-dimensional invariant manifold.

Paper analyzes normal approximation for two-timescale stochastic algorithms, revealing interaction between fast and slow timescales.

problem Non-asymptotic bounds for accuracy of normal approximation in linear two-timescale stochastic approximation algorithms.
method Established bounds for normal approximation in terms of convex distance, focusing on last iterate and Polyak-Ruppert averaging.
result Normal approximation rate for the last iterate improves with increased timescale separation, while it decreases in the averaged setting.

We consider the minimization of a function defined on a Riemannian manifold M\mathcal{M} accessible only through unbiased estimates of its gradients. We develop a geometric framework to transform a sequence of slowly converging iterates generated from stochastic gradient descent (SGD) on M\mathcal{M} to an averaged i…

2018-02-26abs ↗pdf ↗

The aim of this work is to provide fast and accurate approximation schemes for the Monte-Carlo pricing of derivatives in the Lévy LIBOR model of Eberlein and Özkan (2005). Standard methods can be applied to solve the stochastic differential equations of the successive LIBOR rates but the methods are generally slow. We …

2010-06-16abs ↗pdf ↗

Dealing with the shear size and complexity of today's massive data sets requires computational platforms that can analyze data in a parallelized and distributed fashion. A major bottleneck that arises in such modern distributed computing environments is that some of the worker nodes may run slow. These nodes a.k.a.~str…

2018-03-31abs ↗pdf ↗

Boosting is a learning scheme that combines weak prediction rules to produce a strong composite estimator, with the underlying intuition that one can obtain accurate prediction rules by combining "rough" ones. Although boosting is proved to be consistent and overfitting-resistant, its numerical convergence rate is rela…

2015-05-06abs ↗pdf ↗

PrecGD restores linear convergence in over-parameterized nonconvex matrix factorization.

problem Slow convergence of local search algorithms in over-parameterized nonconvex matrix factorization.
method Preconditioned Gradient Descent (PrecGD) with an inexpensive 2\ell_2 regularization.
result PrecGD restores linear convergence rate even in the over-parameterized case.

This work interprets SFA through variational inference, relaxing linearity constraints.

problem Recover non-linear SFA from variational inference.
method Probabilistic interpretation of SFA through variational inference, relaxing linearity constraints.
result Reinterprets SFA as a variational framework, allowing slowness as a regularizer to reconstruction loss.

Active learning can't improve over passive in certain settings.

problem Active learning vs. passive learning in nonparametric settings.
method Analyzing margin conditions and their effects on active learning performance.
result Nuances in margin conditions determine whether active learning can outperform passive learning.

During this last decades, several attempts to construct slow invariant manifold of the Lorenz-Krishnamurthy five-mode model of slow-fast interactions in the atmosphere have been made by various authors. Unfortunately, as in the case of many two-time scales singularly perturbed dynamical systems the various asymptotic p…

2018-08-24abs ↗pdf ↗

We develop a 2D travel time tomography method which regularizes the inversion by modeling groups of slowness pixels from discrete slowness maps, called patches, as sparse linear combinations of atoms from a dictionary. We propose to use dictionary learning during the inversion to adapt dictionaries to specific slowness…

2017-12-16abs ↗pdf ↗

Method learns dynamics of slow variables from stochastic data.

problem Modeling unknown multiscale stochastic systems with limited data.
method Data-driven approach to learn effective dynamics from bursts of observation data.
result Generative model accurately captures effective dynamics of slow variables.

Optimizes convex functions in finite vs infinite dimensions, revealing slow convergence rates.

problem Analyzing gradient flows in finite and infinite-dimensional Hilbert spaces.
method Proves convergence rates and optimality conditions for gradient flows and related methods.
result Gradient flow convergence rates in finite dimensions are slower than in infinite dimensions, with optimal rates achievable in Hilbert spaces.