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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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2555097641,018 · Jun 202019922001200920172026
48 results for sharp sample complexity guarantees

The paper analyzes sampling efficiency of discrete diffusion models, providing sharp and adaptive guarantees.

problem Theoretical foundations of discrete diffusion models, especially sampling efficiency.
method Continuous-time Markov chain (CTMC) formulation, ττ-leaping-based samplers, effective total correlation.
result The ττ-leaping algorithm achieves an iteration complexity of order ildeO(d/ε) ilde O(d/\varepsilon) for uniform discrete diffusion, improving existing bounds by a factor of dd.

Paper develops efficient algorithms for learning rationalizable equilibria in multiplayer games.

problem Learning rationalizable behavior in multiplayer games under bandit feedback.
method New algorithms for finding rationalizable Coarse Correlated Equilibria and Correlated Equilibria with polynomial sample complexity.
result Achieved polynomial sample complexity for learning rationalizable equilibria, improving over existing exponential complexity.

In this work, we propose a robust approach to design distributed controllers for unknown-but-sparse linear and time-invariant systems. By leveraging modern techniques in distributed controller synthesis and structured linear inverse problems as applied to system identification, we show that near-optimal distributed con…

2019-09-21abs ↗pdf ↗

MINTS uses a minimalist Bayesian framework to tackle multi-armed bandits with structural constraints.

problem Sequential decision-making under uncertainty with complex structural constraints.
method Minimalist Bayesian framework with profile likelihood to eliminate nuisance parameters.
result MINTS achieves near-optimal regret guarantees and adapts to unimodal structure.

The paper explores how simplicity leads to better out-of-distribution generalization in models.

problem Understanding the theoretical principles behind out-of-distribution (OOD) generalization in modern models.
method Examining diffusion models in image generation to analyze compositional generalization abilities and develop a theoretical framework for simplicity-based OOD generalization.
result The true, generalizable model corresponds to the simplest among consistent models, and this simplicity can be quantified and used to establish sample complexity guarantees.

The paper analyzes how good initial guesses affect the amount of data needed for low-rank matrix recovery.

problem Theoretical guarantee of local optimization algorithms requires excessive data to prevent spurious local minima.
method Quantifies the relationship between initial guess quality and sample complexity using restricted isometry constant.
result A linear improvement in initial guess quality leads to a constant factor improvement in sample complexity.

New offline RL method handles average-reward MDPs with single-policy coverage.

problem Challenges in offline reinforcement learning due to distribution shift and non-uniform coverage.
method Develops an algorithm based on pessimistic discounted value iteration with quantile clipping.
result First fully single-policy sample complexity bound for average-reward offline RL.

Sharp bounds for high-probability estimation of discrete distributions.

problem Estimating discrete distributions with high probability under χ2χ^2-divergence.
method Sharp upper and lower bounds for the classical Laplace estimator, and characterization of minimax high-probability risk for any estimator.
result Sharp bounds for high-probability estimation of discrete distributions can be achieved through a simple smoothing strategy.

This paper addresses the problem of identifying sparse linear time-invariant (LTI) systems from a single sample trajectory generated by the system dynamics. We introduce a Lasso-like estimator for the parameters of the system, taking into account their sparse nature. Assuming that the system is stable, or that it is eq…

2019-04-20abs ↗pdf ↗

Double descent in portfolio optimization shows improved performance with complexity, then declines, due to overfitting.

problem Improving portfolio optimization performance with model complexity.
method Investigates the relationship between model complexity and out-of-sample performance in mean-variance portfolio optimization.
result Performance of low-dimensional models initially improves with complexity but declines due to overfitting. High-dimensional models show double ascent Sharpe ratio curve.

New research shows DDPM can adapt to data's intrinsic low dimensionality efficiently.

problem Theoretical inefficiency of DDPM in high-dimensional data.
method Investigates how DDPM can exploit intrinsic low dimensionality of data.
result Proves DDPM's iteration complexity scales nearly linearly with intrinsic dimension kk.

Analyzes the complexity of linear hypothesis sets using Rademacher complexity.

problem Understanding the complexity of linear hypothesis sets for various norms.
method Tight analysis of empirical Rademacher complexity for linear hypothesis classes with bounded weights.
result Improved bounds on Rademacher complexity for linear hypothesis sets, matching or improving existing results.

Study the impact of overfitting on linear predictive models' performance.

problem Overfitting reduces the out-of-sample performance of linear predictive trading strategies.
method Computed in- and out-of-sample means and variances of PnLs to derive replication ratios.
result Replication ratio diminishes for complex strategies with many assets.

Sharp statistical theory for conditional diffusion models.

problem Lack of theoretical foundation for conditional diffusion models.
method Sharp statistical theory with approximation of conditional score function.
result Sample complexity bound that adapts to data distribution smoothness.

Improved model-based reinforcement learning for multi-agent Markov games.

problem Suboptimal sample complexity for model-based algorithms in multi-agent reinforcement learning.
method Optimistic Nash Value Iteration (Nash-VI) for two-player zero-sum Markov games.
result First model-based algorithm matching information-theoretic lower bound with improved sample complexity.

New algorithms achieve uniform-PAC guarantees for RL with bounded eluder dimension.

problem Achieving strong performance guarantees in reinforcement learning.
method Proposes algorithms for nonlinear bandits and model-based episodic RL with a bounded eluder dimension.
result Achieves uniform-PAC sample complexity that matches state-of-the-art regret bounds or sample complexity guarantees.

Sharp sample complexity for multiclass PAC learning with bandit feedback.

problem Multiclass PAC learning with bandit feedback.
method Characterization of optimal sample complexity using a new combinatorial dimension (bandit DS dimension) and a learning algorithm (ListCascade).
result Sharp sample complexity characterization for every concept class up to logarithmic factors.

EM algorithm converges linearly and achieves sharp rate in estimating mixtures of pairwise differences.

problem Estimating mixtures of pairwise differences from noisy data.
method Sharp analysis of the EM algorithm locally around the ground truth.
result The EM sequence converges linearly with an \ell_\infty-norm guarantee on the estimation error and achieves the sharp rate of estimation in the 2\ell_2-norm.

This work extends diffusion models to handle heavy-tailed targets, improving score estimation and sampling guarantees.

problem Score estimation and sampling guarantees for heavy-tailed targets in diffusion models.
method Kernel density estimation and minimax rates analysis for score estimation and sampling guarantees.
result Sharp minimax rates for score estimation and sampling guarantees for heavy-tailed targets, revealing qualitative differences between exponential and polynomial tails.

This paper provides theoretical insights into why and how deep learning can generalize well, despite its large capacity, complexity, possible algorithmic instability, nonrobustness, and sharp minima, responding to an open question in the literature. We also discuss approaches to provide non-vacuous generalization guara…

2017-10-16abs ↗pdf ↗

Algorithm recovers factors of rank-1 matrices from noisy measurements.

problem Estimating factors of a rank-1 matrix from nonlinearly transformed and noisy measurements.
method Alternating minimization with random initialization and analysis of empirical error recursion.
result Algorithm converges geometrically fast from random initialization, with sharp guarantees.

Unified framework for model-based RL with sample complexity guarantees.

problem Designing efficient posterior sampling methods for model-based RL.
method Optimistic posterior sampling, Hellinger distance reduction, data likelihood measurement.
result Unified algorithms with state-of-the-art sample complexity guarantees.

Sharp bounds for Dirichlet sums lead to improved Bayesian algorithm analysis.

problem Improving Bayesian algorithm performance through precise deviation bounds.
method Novel integral representation of Dirichlet sum density, Gaussian approximation, complex analysis.
result Significantly sharpened regret bounds for Multinomial Thompson Sampling.

Efficiently learns polytrees with known skeleton in polynomial time and sample complexity.

problem Learning polytrees with known skeleton structure.
method Proposes an efficient algorithm for learning dd-polytrees in polynomial time and sample complexity when the skeleton is known.
result Establishes finite-sample guarantees for efficient learning of dd-polytrees.

Paper analyzes asymmetry in LoRA initialization for foundation models.

problem Asymmetry in LoRA initialization affects generalization of foundation models.
method Theoretical analysis of asymmetric LoRA with frozen random factors.
result Upper bound on sample complexity of $ ilde{\mathcal{O}}\left(\frac{\sqrt{r}}{\sqrt{N}} ight)$ with high probability.

This work improves SGMs' convergence guarantees for semiconvex distributions with discontinuous gradients.

problem Establishing convergence guarantees for SGMs under weak regularity conditions.
method Developed non-asymptotic Wasserstein-2 convergence analysis for SGMs targeting semiconvex distributions with discontinuous gradients.
result Achieved optimal dependence of O(d)O(\sqrt{d}) on data dimension dd and convergence rate of order one.

We study learning problems in which the underlying class is a bounded subset of LpL_p and the target YY belongs to LpL_p. Previously, minimax sample complexity estimates were known under such boundedness assumptions only when p=p=\infty. We present a sharp sample complexity estimate that holds for any p>4p > 4. It is b…

2020-02-04abs ↗pdf ↗

Study tests whether trade-off functions are above or below benchmarks using finite samples.

problem Testing trade-off functions between unknown distributions.
method Identifies a condition for nontrivial testing, constructs a test with error guarantees, and inverts the test for confidence bands.
result Finite-sample testing is possible under specific structural assumptions about rejection regions.

Paper analyzes sample complexity for offline ff-divergence-regularized contextual bandits.

problem Lack of tight analyses for sample complexity in offline reinforcement learning.
method Novel pessimism-based analysis for reverse KL divergence, establishing ildeO(ε1) ilde{O}(ε^{-1}) sample complexity.
result Achieves ildeO(ε1) ilde{O}(ε^{-1}) sample complexity for reverse KL divergence, surpassing existing bounds.

New algorithms reduce sample complexity for multiclass contextual bandits.

problem Designing efficient algorithms for multiclass contextual bandits with sparse rewards.
method Two complementary approaches: decision-estimation coefficient analysis and low-variance exploration.
result Achieved optimal sample complexity bounds for multiclass contextual bandits.

New bounds improve generalization in learning scenarios.

problem Limitations of existing information-theoretic bounds in SCO problems.
method Sample-conditioned hypothesis stability and neighboring-hypothesis matrix.
result Sharper generalization guarantees in various learning scenarios.

The study establishes minimax bounds for estimating operators from noisy samples.

problem Estimating unknown operators between Hilbert spaces from noisy data.
method Developed a minimax theory for uniformly bounded Lipschitz operators, proving lower and upper bounds.
result Sharp characterizations of minimax risk for generic Lipschitz operators, showing a curse of sample complexity.

Study improves sampling from non-log-concave distributions using Fisher information.

problem Sampling from non-log-concave distributions with high Fisher information guarantees.
method Proximal sampler with RGO implementation, leveraging log-concave sampling results.
result Improved complexity guarantee in relative Fisher information for non-log-concave sampling.

OPSRL algorithm reduces regret with few samples in reinforcement learning.

problem High regret in reinforcement learning with limited data.
method Optimistic Posterior Sampling (OPSRL) with logarithmic sample complexity.
result Guaranteed high-probability regret bound of O~(H3SAT)\widetilde{\mathcal{O}}(\sqrt{H^3SAT}).

Sharp convergence analysis for nonconvex regression models.

problem Nonconvex optimization in regression models with normally distributed covariates.
method Gaussian comparison theorems for analyzing iterative algorithms.
result Sharp global convergence rates for various statistical models.

V-learning tackles multiagent reinforcement learning by reducing sample complexity.

problem Curse of multiagents in multiagent reinforcement learning.
method V-learning is a fully decentralized algorithm that learns Nash, correlated, and coarse correlated equilibria.
result V-learning achieves sample complexity that scales with the maximum number of actions per agent, not the joint action space.